Got me a couple problems

[Bad bow tie]

So for a while now my Tahoe has been pissing me off. It's a 1995 with 188,000 miles. When driving, and I start coasting with my foot barely touching the gas, it starts to jerk/buck back and forth. This is imminent at pretty much any speed, but more noticiable at lower speeds like 50 mph and below. Second, when the truck is warm it hesitates on take off. It doesn't seem to happen all the time, just when warm.

As of Monday 6/8, I have replaced:
AC Delco spark plugs gapped at .035"
AC Delco plug wires
AC Delco cap and rotor
AC Delco throttle position sensor (TPS)
Oil change with Mobil 1 and an AC Delco filter since I caught shit over on tahoe forum for using Fram.
Seafoamed it twice which helped out considerably with the hesitation but nothing for the jerking. (probably 2-3 months ago)
And I soaked the throttle body in carb cleaner a couple months ago...

I really thought this tune up would have cured it especially with the new TPS senor. It seems to have helped it but did not stop it. Plugs and wires looked fine but I decided to change them anyway. The cap and rotor looked like shit. All vacuum lines seem to be in place and secure. Other than this, it runs fine.

What do you guys think? I'm lost with it and getting really pissed off. :emotions122:

[Sepiroth]

You might want to remove your EGR and Idle Air Control motor. Soak them in carb cleaner and try to remove as much carbon as possible.

Without actually looking at the vehicle, this is the best I can do for now.

[jmildoc]

so soaking the egr does what exactly?

[Bad bow tie]

It is not stalling, never has. Sometimes when it hesitates it feels and sounds like it is going to stall but never has. This is especailly true when I'm in reverse. It sputters and feels like it is going to stall, but after a few seconds it jumps right back up. I'll clean the idle air control motor and see if that changes anything.

[Sepiroth]

Also clean the EGR and EGR passages.

Doing so knocks and gets rid of any built up carbon deposits that would allow the EGR tp remain partially open while it is not supposed to be, thus causing the bucking sensation.

But it could be other things as well. Doing what I posted would help regardless.

[bowtiefreak]

My vote is EGR, had that happen on my s-10.

[blueflamed03]

fuel filter been replaced?

[Bad bow tie]

fuel filter been replaced?

Yeah, I replaced the fuel filter like 1500 miles ago thinking that may have been part of the issue. No change. K&N air filter is also clean.

[malones99]

How exactly do you clean the EGR?

[clean454]

unplug the vacuum line on the egr start the truck and drive it, if it runs fine and smooth its the egr valve behind the air cleaner on the passenger side, mine was doing the same thing, ive have had it unplugged for like 6 months now lol just havent had the time to replace it, its simple and easy,

[Sepiroth]

9/10 times cleaning it will do the trick.

[AtomicHoe094]

i replaced my egr like 3 months ago. it was about 90 bucks i remember.. super easy to uninstall and to install.. not sure if your one of those people that it has to be replaced and not just "cleaned".. You pop any codes??

[malones99]

there isn't a vac line on my EGR? 99 Yukon OBS.

[AtomicHoe094]

should be..

[Bad bow tie]

I will take a look at it when I get home from work in a hour and a half. I fuckin hate 10 hour days. I'll unplug to vacuum line and see if it runs any better.

i replaced my egr like 3 months ago. it was about 90 bucks i remember.. super easy to uninstall and to install.. not sure if your one of those people that it has to be replaced and not just "cleaned".. You pop any codes??

If I can clean something to fix it instead of just replacing it, you better believe I will. I am always game for saving money especially in this economy. And I don't have a check engine light on. Wonder if it even works...I don't think it's ever come on. lol

[AtomicHoe094]

mine would comon like 10 min of straight freeway driving only.. if i was driving around city for 5 hrs it wouldnt come on.. but yet i replaced the egr and its still on.. wtf.. lol.. but hmm
so try cleaning it out..

[clean454]

I will take a look at it when I get home from work in a hour and a half. I fuckin hate 10 hour days. I'll unplug to vacuum line and see if it runs any better.



If I can clean something to fix it instead of just replacing it, you better believe I will. I am always game for saving money especially in this economy. And I don't have a check engine light on. Wonder if it even works...I don't think it's ever come on. lol

mines like 60 bucks on a 95 obd 1, the little diaphragm in mine was broken i just got a new one, i don't trust trying to fix old parts, i like just to replace it, but that's me, its just 2 screw and a gasket to replace it,

and yes there's a vacuum line you will see it clearly! behind the air cleaner passenger side good luck!

[AtomicHoe094]

the 96 and above vortec motors.. the egr is in the front i thought....... (fillmein)

[clean454]

the 96 and above vortec motors.. the egr is in the front i thought....... (fillmein)

yeah but bad bow tie has a 95'

["350Vortec"]

Wish i knew where the egr and air cleaner were on my 96 hoe, I want to clean mine. My truck seems to be doggy and sluggish when punching it at speeds over 50.

[AtomicHoe094]

air cleaner?? comon man i know you know where thats at~ its that black box on the passenger side that goes into the fender.. you have to take that apart to get to the filter part..

Egr on your vortec is in front of the motor.. im not sure where exactly, i dont have a vortec.... different yrs had diff locations ..

[qlc1964]

do the sea foam.

[hapyspaz]

once you clean the IAC (idle air controler) and clean the EGR, tap on the IAC lightly while you have it running. Much like a mass air sensor, if it is going bad it will choke the engine.

Here is the EGR location on the vortecs, right next to the thermostat. This image shows the intake with a restrictor plate in place.

http://i40.photobucket.com/albums/e227/mykk/Project%20383ci/rockers.jpg

[Bad bow tie]

Chalk another onto the list...

Well, I didn't get around to cleaning the EGR. Want to know why? I encountered another problem on my way home from work yesterday. I was on the freeway doing a modest 72 mph, when all the sudden I had a terrible vibration. This has been an ongoing problem but it has never been this bad. It seemed to start getting worse when I had to pull my buddy out of a mud hole down this nasty ass two track made for quads. That was last weekend. It was coming from the rear so I thought I had kicked a wheel weight or the u-joints were finally going. It did it my entire ride home which is an hour. IT seemed to quit as soon it down shifted to a lower gear or when I let off the gas. When I got home, I put it up on stands and took a look at the u-joints. Holy shit, they were as loose as a working girl's snatch. I couldn't believe how much play there was. The one on the back of the drive shaft that connects to the rear diff was missing all the needle bearings inside the cap and had actually worn down the stud on the actual u-joint. I am surprised it didn't break on the freeway leaving me stranded; especially with Michigans shitty roads. (potholes everywhere) So I go to local parts store and buy two new ones to replace both in the back. Drive shaft came off easy, put the one on the rear of the shaft in. The one that connects the shaft to the tranny was sort of a bitch but I eventually got it out. I was about to put the new one in when I noticed a hair line crack running across the circular part of the yoke. So now I have to go the junk yard and see if I can find a new yoke to put in. I didn't want to re-install the cracked one. So right now she is sitting in the garage on jack stands awaiting the new yoke while I'm driving the new Silvy. I just wonder if this was a contributing factor in the bucking/jerking sensation. I guess we'll see.

[AtomicHoe094]

badbowtie- damn sounds intense man.. lol.. when was the last time you replaced those or looked under your truck?? lol

[Bad bow tie]

It was a memorable experience. My money is on them being original from the factory. They had the grease zerk on them and said "forged in the USA" or something along those lines. Crazy thing is I'm under there all the damn time checking shit out. Good news is I bought a new used drive shaft with a good slip yoke and all new u-joints for $50. One of the bone yards I called wanted $195 for just the yoke. I will install it when I get out of work. Hopefully one, maybe two problems are solved.

[Sepiroth]

Thats some scary stuff mang. I hope it works out for you.

[AtomicHoe094]

thats a good find! by the time you buy 2 new ujoints your already spending 40 something bucks....

[Bad bow tie]

haha...I spent $36 on two new ones from autozones last night. They were the white lithium grease ones that you never have to service and carry a lifetime warranty. I'm going to bang them out and try to return them. No sense in having them anymore.

[AtomicHoe094]

good call.. lol.. so i was close.. 37=40 lol..

[Bad bow tie]

Love the new lay out...

So I checked the EGR valve last night and thats not the issue. It moves freely as it should. I hooked a vacuum up to it and it bogged the engine and made it sputter like it should. I also ran a vacuum test and everything checked out good. It has a rough idle and sort of vibrates down the road. I rechecked the plugs, wires, cap, and rotor which are all good. So what could it be? Two other things I thought of was maybe the timing is off or I have a clogged cat. Not sure about the cat though.

[Bad bow tie]

Well I decided to check the wires one last time and found one of them to have a cut in the boot. This was not giving it a connection. So it was running on 7 cylinders. I took the wire down to the parts store where I got them and they replaced it free of charge. Went home slapped it on, and problem solved. I think the new drives shaft and u-joints fixed the jerking/bucking. The hesitation is very very minimal now. I still don't know whats causing that.

Thanks everyone who helped me get the hoe healthy again! Now I'm going to go outside and wash all the mud and crap off her thats been there for a week.

[AtomicHoe094]

welll thats good to hear man.. glad you got most of it figured out..