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

[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.