07' Tahoe LT 4x4-Engine RPM Problem Post-Corvette Servo Install/Service

[mackmcmillan]

Hi all,

I need your help!

I did an admittedly cursory search but nothing jumped out at me so I'm here to humbly ask if anyone has had an issue after ANY type service that would cause this condition? Could the servo install have caused this?

In traffic, I have to press as though I have no brake booster to get to a full stop and have to maintain that pressure to keep it still. Even at idle it picks up RPMs and speed if I'm not on the pedal. It's similar in feel to a cammed ride that lurches, except mine just stays at 3,000. Unless I stomp the brake then occasionally it remembers to slow itself.

Sitting still at a light, I tried neutral, but all that did was free up the engine to rev even higher. Not redlined, but they stayed up enough it took 3 gallons of gas to drive less than 15 miles today.

I've had little electrical gremlins here and there since I got it being the first year out but those were dealt with years ago. Throttle body isn't sticking, pedal doesn't do anything unusual, either, so I don't think the drive-by-wire would be tricking it in this fashion.

The Tahoe's old and has been well used, so I expect things to go as they do, but THIS? I hate taking my ride in to upgrade it to avoid making a costly shadetree mechanic error only to have it come back worse than it was when I left it.

It had numerous mechanical things that went "bad" in close succession, so I thought I'd get all the troubles fixed and upgrade it while it was already there and save my back the hassle...

I just wanted the servo to help the outdated 4L60E not be such a POS in this vehicle. The shift points are terrible, it never knows where it should be and downshifts on an ant hill but will stay in overdrive in the mountains... So it's sucked forever in that regard. And apparently, I've only succeeded in achieving the opposite by kicking it over the hill and killing it. At least any want to ever touch it again. I'm sick of the GM nightmare, but they don't pay well when they retire ya, so I'm stuck with this thing now.

The crummy thing is, I happen to love the darned thing. Not to mention it's the only ride my kid has ever known me to have and she loves it too. It's one of our bonding things and she's a teen now, so it's getting less and less. Wanna keep the fun until the hormones completely eff it up!

Someone, anyone, please let me know what I can do besides another mechanic and even MORE of my retirement check and no guarantees they'll find f*** all or everything needs replaced. I'm at a loss for this and one other issue, actually. May as well toss it in while I'm on my soapbox: I go through front tires in less than 2 years. All I ever get is "It's in spec," a shove off, and a lighter wallet (trend...). I get frustrated by that because I can plainly see how far off the camber is. The bottom of the tire is a good inch or more further out than the top on both sides and the wear pattern confirms it. I am sick of buying tires so often as well. Anyone else have THAT long term problem of horrid tire wear?

My apologies for the flippin' novela, I'm just so overwhelmed at how much is still troublesome even after I throw money at it as though I actually HAVE it to be doing so.

Any help is greatly appreciated, and you can bet I'll certainly read anything anyone has to offer! That said, if I don't reply, it truly won't be anything personal!

Thank you in advance for your time, I do value your input!

V/R,

-Mack

E. McMillan
I.Y.A.A.Y.A.S.

 

[iamdub]

Hi all,

I need your help!

I did an admittedly cursory search but nothing jumped out at me so I'm here to humbly ask if anyone has had an issue after ANY type service that would cause this condition? Could the servo install have caused this?

In traffic, I have to press as though I have no brake booster to get to a full stop and have to maintain that pressure to keep it still. Even at idle it picks up RPMs and speed if I'm not on the pedal. It's similar in feel to a cammed ride that lurches, except mine just stays at 3,000. Unless I stomp the brake then occasionally it remembers to slow itself.

Sitting still at a light, I tried neutral, but all that did was free up the engine to rev even higher. Not redlined, but they stayed up enough it took 3 gallons of gas to drive less than 15 miles today.

I've had little electrical gremlins here and there since I got it being the first year out but those were dealt with years ago. Throttle body isn't sticking, pedal doesn't do anything unusual, either, so I don't think the drive-by-wire would be tricking it in this fashion.

The Tahoe's old and has been well used, so I expect things to go as they do, but THIS? I hate taking my ride in to upgrade it to avoid making a costly shadetree mechanic error only to have it come back worse than it was when I left it.

It had numerous mechanical things that went "bad" in close succession, so I thought I'd get all the troubles fixed and upgrade it while it was already there and save my back the hassle...

I just wanted the servo to help the outdated 4L60E not be such a POS in this vehicle. The shift points are terrible, it never knows where it should be and downshifts on an ant hill but will stay in overdrive in the mountains... So it's sucked forever in that regard. And apparently, I've only succeeded in achieving the opposite by kicking it over the hill and killing it. At least any want to ever touch it again. I'm sick of the GM nightmare, but they don't pay well when they retire ya, so I'm stuck with this thing now.

The crummy thing is, I happen to love the darned thing. Not to mention it's the only ride my kid has ever known me to have and she loves it too. It's one of our bonding things and she's a teen now, so it's getting less and less. Wanna keep the fun until the hormones completely eff it up!

Someone, anyone, please let me know what I can do besides another mechanic and even MORE of my retirement check and no guarantees they'll find f*** all or everything needs replaced. I'm at a loss for this and one other issue, actually. May as well toss it in while I'm on my soapbox: I go through front tires in less than 2 years. All I ever get is "It's in spec," a shove off, and a lighter wallet (trend...). I get frustrated by that because I can plainly see how far off the camber is. The bottom of the tire is a good inch or more further out than the top on both sides and the wear pattern confirms it. I am sick of buying tires so often as well. Anyone else have THAT long term problem of horrid tire wear?

My apologies for the flippin' novela, I'm just so overwhelmed at how much is still troublesome even after I throw money at it as though I actually HAVE it to be doing so.

Any help is greatly appreciated, and you can bet I'll certainly read anything anyone has to offer! That said, if I don't reply, it truly won't be anything personal!

Thank you in advance for your time, I do value your input!

V/R,

-Mack

E. McMillan
I.Y.A.A.Y.A.S.

You may get better help if this was in the correct forum. You posted it in the '91-'99 forum. Can we get an admin to help? @NathanJax ?

SES light on? Sounds like a bad vacuum leak. I don't know what your mechanic would've been doing with anything in the engine bay if they were just installing a trans servo. You'll burn up your torque converter soon if you don't fix this. I assume it immediately revs high as soon as you start it? Pop the hood and check for anything obvious, particularly a loose or disconnected vacuum hose going to the brake booster. A leak here would be a double-edged sword, causing a high idle and weak braking power.

Having visible negative camber is NOWHERE near "spec" and may very well be dangerous. If your ball joints and/or control arm bushings are that bad, you may be pressing your luck. Have you ever jacked it up and shook each wheel to feel for slack? Gonna have to put some ass into it cuz them wheels and tires are around 80 lbs. There's a chance it's just out of alignment, maybe from someone messing with the upper control arm bolts at one point in the past. If you brought it to a place that offers a free alignment check, they'll be sure to not only put numbers to it but also find worn components. Any place worth a lick isn't gonna try to align a vehicle in need of new suspension and/or steering parts.

 

[HiHoeSilver]

Chris has given some good starting points here. I have one question to add.
You say the throttle body isn't sticking. Did you happen to play with the butterfly plate by hand?

 

[mackmcmillan]

I'm not sure how it decided to file itself in that forum, but shit, alright. If the admins could help me out, that'd be swell. I don't like to create posts in the first place so it's not surprising I'd find out how to screw it up.

No lights, no codes. All the codes and whatnots have been remedied. They were what brought me to getting it fixed to begin with when this was not a problem. I thought vacuum as well but I saw nothing out of the ordinary both at first glance in the off position then while running, etc. The mechanic was in the engine bay long enough to change the oil and top some fluids, but regardless of particulars, the thing didn't do this before I got it back.

Luckily, I drove it home and parked it. Being retired and nowhere to go helps. But at some point, It'd be nice to have a dependable vehicle. I certainly paid for one and then some over the years with this money pit. It doesn't seem like GM is the way to go anymore. Haven't found one they make that isn't a subpar bag of bolts made in China. No wonder folks leave the big 3 for foreign cars. I can get a 2JZ anything I want that'll run after taking buckshot but this won't run right if you do everything right. Every time you touch one of these monstrosities, it costs an arm and a leg as well as nothing is ever completely fixed. It's always a limp-on 'til the next major failure. If I could afford to, I'd get rid of it. Just about ready to take it out to the desert and make a target out of the damn thing. Cost all this money and 10 years later even while keeping up with everything, it all goes to shit... This isn't normal wear and tear, either... I have taken good care of it. Yet all it does is break.

You're telling ME about the camber, etc... I can't force these ******* to do anything more. They say it's in spec while looking at the wheel leaning off my ride. Not just one place mind you, several. So, yeah, whatever their "spec" sheet says is utter garbage or they are ***** as well.

The damn wheel hubs go bad all too often as well. An 07 and I've put at least that many sets of them on. That leads me to think the thing was jacked from day 1...

I'm pretty well flustered by this whole day and that was the coup-de-grace. I've literally had the damn thing back a DAY. I drove it ONCE.

If you respond, I'll see it when I can but I have to get off this thing and stop thinking on it before a wall eats a keyboard.

 

[mackmcmillan]

By hand this very day as well as cleaning off anything that might have been there.

 

[iamdub]

If it was doing this as soon as the mechanic gave it back to you, you should've turned right around and had them fix it.

By hand this very day as well as cleaning off anything that might have been there.

So, the mechanic did this or you did in trying to fix it?

 

[mackmcmillan]

If it was doing this as soon as the mechanic gave it back to you, you should've turned right around and had them fix it.



So, the mechanic did this or you did in trying to fix it?

We BOTH did the inspection in the parking lot, and he had the rag and cleaner. We didn't both need to wipe it down.

Forgive this next part as I often end up getting into it with idiots on YT who think it's great always being negative and plain ****** to people, and your question felt loaded so bear with it.

I feel like you wanna say something... Out with it. I'm more than capable with a wrench no matter how I chose to portray my skill set. I prefer to be humble and not act like I think of myself as some ASE certified guru. Fixed my first Massey-Ferguson combine after my grandfather gave up. I was 10. That said, I can assure you I didn't magically eff up cleaning and inspecting a throttle body plate. I hope I'm wrong here and if so, please accept my sincerest apologies. I just never like feeling as though my intelligence is being called into question. Cheers!

 

[mackmcmillan]

The mechanic was my first stop when it decided to get noticeably ugly... Again, not completely clueless how the world works my friend. Taking it back and getting anything DONE worthwhile, however, is a different issue altogether.

 

[iamdub]

We BOTH did the inspection in the parking lot, and he had the rag and cleaner. We didn't both need to wipe it down.

Forgive this next part as I often end up getting into it with idiots on YT who think it's great always being negative and plain ****** to people, and your question felt loaded so bear with it.

I feel like you wanna say something... Out with it. I'm more than capable with a wrench no matter how I chose to portray my skill set. I prefer to be humble and not act like I think of myself as some ASE certified guru. Fixed my first Massey-Ferguson combine after my grandfather gave up. I was 10. That said, I can assure you I didn't magically eff up cleaning and inspecting a throttle body plate. I hope I'm wrong here and if so, please accept my sincerest apologies. I just never like feeling as though my intelligence is being called into question. Cheers!

Not loaded at all, and I'm one to speak my twisted little mind. I have no reason nor intention to be one of "those guys" towards you. That's not TYF style. Just trying to help by getting as accurate of info as possible- piecing the story together in the actual order of events, etc. I was merely asking for clarification since I understood the story as you got your Tahoe back from the mechanic with it acting up but you continued home, then later wiped down the TB in effort to fix it. We can only go by text on a screen and sometimes pictures so there's a huge communication barrier to contend with. Don't take offense if some questions come across as sophomoric or insulting. See it from our side.

As Nate was leading on, manually turning with a drive-by-wire (DBW) throttle body can really screw it up.

 

[mackmcmillan]

Not loaded at all, and I'm one to speak my twisted little mind. I have no reason nor intention to be one of "those guys" towards you. That's not TYF style. Just trying to help by getting as accurate of info as possible- piecing the story together in the actual order of events, etc. I was merely asking for clarification since I understood the story as you got your Tahoe back from the mechanic with it acting up but you continued home, then later wiped down the TB in effort to fix it. We can only go by text on a screen and sometimes pictures so there's a huge communication barrier to contend with. Don't take offense if some questions come across as sophomoric or insulting. See it from our side.

As Nate was leading on, manually turning with a drive-by-wire (DBW) throttle body can really screw it up.

He cleaned the plate, and it seemed to have had no bearing on it in this instance. It was acting in the same manner (poorly) as it had before.


Thanks to you both and thanks for understanding my butthurt / thin-skin... I swear when they finally ruined me too much to be useful then sent me out to pasture I became a huge pansy... Between that and folks seeming to line up for a chance to bring others down anymore and I let it get the better of me. I made an ass of myself and assumed (to a degree) when I should not have. Consider my wrist thoroughly slapped, please! ;-) I should have thought better of my reply, but I figure it's best to know!

 

[iamdub]

He cleaned the plate, and it seemed to have had no bearing on it in this instance. It was acting in the same manner (poorly) as it had before.


Thanks to you both and thanks for understanding my butthurt / thin-skin... I swear when they finally ruined me too much to be useful then sent me out to pasture I became a huge pansy... Between that and folks seeming to line up for a chance to bring others down anymore and I let it get the better of me. I made an ass of myself and assumed (to a degree) when I should not have. Consider my wrist thoroughly slapped, please! ;-) I should have thought better of my reply, but I figure it's best to know!

No offense taken here. I see it from your side- you're frustrated and feeling defeated by your vehicle and people in general; and emotions absolutely affect perception. I applaud you for standing firm in your confidence and not just taking what you had perceived as "shit slinging" towards you. Have a drink, a smoke, a pill, a **** or maybe a good night's rest... Whatever to chill and clear your mind so we can figure this out.

So, starting fresh, I'm gonna recap how I'm understanding the story:

1) You had a mechanic install a Corvette servo in your Tahoe that was idling and driving [relatively] normally prior to the servo installation

2) Upon your mechanic completing the servo installation as well as an oil change and topping off of fluids, your Tahoe then idled around 3,000 RPM (or higher)

3) Your mechanic attempted to fix the new issue by manually opening the throttle and wiping it with a rag, which made no improvement

4) You drove it home, parked it and began researching for answers

 

[mackmcmillan]

I can't find fault in the overall picture as painted, good sir. As far as that mechanic... Nice enough guy but lesson learned. I honestly wasn't interested in leaving it there any longer and knew if ever there was a mecca of knowledge, this was it. I'd hoped someone would have had a similar issue that had to deal with it and came out victorious. It's always one issue or another with this thing. And while true for all things, I can't help but see it as overboard for something that costs as much as they did/do/will. Hell, I still have the Takata frag grenade in the steering wheel. Sent the memo just to say we know it's messed up, but we have no timetable to fix it, you should be GTG. Doesn't bode well given the history.

 

[HiHoeSilver]

Not loaded at all, and I'm one to speak my twisted little mind. I have no reason nor intention to be one of "those guys" towards you. That's not TYF style. Just trying to help by getting as accurate of info as possible- piecing the story together in the actual order of events, etc. I was merely asking for clarification since I understood the story as you got your Tahoe back from the mechanic with it acting up but you continued home, then later wiped down the TB in effort to fix it. We can only go by text on a screen and sometimes pictures so there's a huge communication barrier to contend with. Don't take offense if some questions come across as sophomoric or insulting. See it from our side.

As Nate was leading on, manually turning with a drive-by-wire (DBW) throttle body can really screw it up.

He cleaned the plate, and it seemed to have had no bearing on it in this instance. It was acting in the same manner (poorly) as it had before.


Thanks to you both and thanks for understanding my butthurt / thin-skin... I swear when they finally ruined me too much to be useful then sent me out to pasture I became a huge pansy... Between that and folks seeming to line up for a chance to bring others down anymore and I let it get the better of me. I made an ass of myself and assumed (to a degree) when I should not have. Consider my wrist thoroughly slapped, please! ;-) I should have thought better of my reply, but I figure it's best to know!

Well said, Chris.

Ernest, welocme to the forum and sorry for coming off as a loaded question. I sould have put a little more info as to why I asked. As Chris said, you'll find that it's not the general way of this forum to just sling at guys. The VAST majority of members here will bend over backwards to help. Many of us have a tendency to think out loud along the way. It just helps some of us really fill in all the details and overcome the inherent shortfalls of the keyboard as Chris said. If someone is inaccurate in their account along the way, point it out. It helps.

As Chris said, I asked about the throttle plate because moving it by hand can really jack up the idle and cause it to act as you've described. We have seen many, "I cleaned my throttle body and now my idle is 2500" threads. There are some relearn "procedures," but they're 50/50 shots. The usual answer is to drive it. It will relearn idle in time.

I'm still a little unclear about the order of things, though. Can you say definitively whether the high idle happened before or after anyone messed with the throttle body?

 

[mackmcmillan]

Well said, Chris.

Ernest, welocme to the forum and sorry for coming off as a loaded question. I sould have put a little more info as to why I asked. As Chris said, you'll find that it's not the general way of this forum to just sling at guys. The VAST majority of members here will bend over backwards to help. Many of us have a tendency to think out loud along the way. It just helps some of us really fill in all the details and overcome the inherent shortfalls of the keyboard as Chris said. If someone is inaccurate in their account along the way, point it out. It helps.

As Chris said, I asked about the throttle plate because moving it by hand can really jack up the idle and cause it to act as you've described. We have seen many, "I cleaned my throttle body and now my idle is 2500" threads. There are some relearn "procedures," but they're 50/50 shots. The usual answer is to drive it. It will relearn idle in time.

I'm still a little unclear about the order of things, though. Can you say definitively whether the high idle happened before or after anyone messed with the throttle body?

Many thanks and a welcome change from the norm of Negative Nancy's nowadays. It was acting up prior to said cleaning... I almost wish it weren't the case if an eventual relearn process might be a remedy to watch for! Hehe

 

[iamdub]

So, it was fine before you brought it to the shop to get the servo installed and oil changed and idling high AFTER the mechanic did the work and continued after his cleaning of the TB.

Replacing the servo or changing the oil and topping of fluids would have nothing to do with anything that affects idle. Maybe they inadvertently damaged something in the areas they were working in? It's odd that you have no SES light. Is your engine fairly dusty? My point is you can see if there's any dust wiped off from anything they may have messed with. Maybe they spilled some oil on a wire harness (such as the one to the TB) and it was pulled a little while they were wiping it clean, breaking a connection in the circuit. The plugs are known to be fragile and there are even replacement plug with wire pigtail kits specifically for this because it is such a common failure. Still, I'd imagine it'd be something that'd produce a DTC.

Did they check the air filter, as many shops do during an oil change? Maybe they popped the hose loose around the MAF or TB when pulling up on the intake tube. Pulling upward on the tube would cause an opening at the bottom of the tube, so it won't be easily seen.

Did they disconnect the battery while they were working on it and the PCM was reset? This can cause it to have to relearn idle, but it shouldn't act like you're describing. Usually it's a "stall once or twice then rev up and down while it relearns" experience.

 

[mackmcmillan]

I will look at all these when I can! I'm disabled from my chosen profession, so when I do something too much one day, I pay in spades for the next several weeks. That said, it's not quite but darn close to bedridden. I will say I was looking around at everything and nothing seemed amiss. However, my very cursory peep wouldn't be sufficient to answer you truthfully, amigo. Give me a little time, I'll manage to get outside and down the stairs ASAP!

 

[iamdub]

No worries. Take care of yourself first and foremost. We'll be here.

 

[jwth]

maybe a couple of things easy to do....
there is a semi flexible line that is held into the intake manifold by a small bolt on an ear on the line and the nipple that goes into the intake is sealed with an o ring. it could have been bumped out of position partially since it is just to the right and back of the throttle body.
GET a can of spry de-greaser or carb cleaner and put in the long plastic hose. start the engine and just spray little hits around any hoses and connections attached to the intake,,,any change in engine rpm will tell you where the problem is.

the plastic intake cover on the vortec's is right at most of the lines and I know from experience that if they get bumped they can crack or dislocate and that will give you an air leak that certainly helps the engine rpm run high.


just a thought

 

[mackmcmillan]

maybe a couple of things easy to do....
there is a semi flexible line that is held into the intake manifold by a small bolt on an ear on the line and the nipple that goes into the intake is sealed with an o ring. it could have been bumped out of position partially since it is just to the right and back of the throttle body.
GET a can of spry de-greaser or carb cleaner and put in the long plastic hose. start the engine and just spray little hits around any hoses and connections attached to the intake,,,any change in engine rpm will tell you where the problem is.

the plastic intake cover on the vortec's is right at most of the lines and I know from experience that if they get bumped they can crack or dislocate and that will give you an air leak that certainly helps the engine rpm run high.


just a thought

Most definitely will add this to the list of checks. Many thanks!

 

[wjburken]

Most definitely will add this to the list of checks. Many thanks!

What part of the country are you located? Might be some fellow TYF guys in your area that might be able to lend a hand.