99 1500 5.3 z-71 Sierra manual linkage throttle body / gas peddle stick / diff rebuild issue

[EasternSierraCQ]

Curious to know if anyone has worked through this:  sticking throttle butterfly (perhaps butterfly?) got to where is was causing jump starts.  I tried a thorough R&R and cleaning of the t body / inspecting to see if a rub or catch point was detected at the closed position.  This did not help and it was at this point my web journey turned up that many were just spending the $400 on a new t body and .. that  dealer had fix bulletin (that I couldn't find this morning) that included using a TB sensor and aligning it digitally.  I did buy and install both sensors on the TB and thought I had it licked but even though I did get the stick to got away with a tiny adjustment to the idle screw (closed [sticking] position) I now have the start of a fluctuating throttle after it initially worked fine.  I initially thought the t body sensor may have been the culprit but instead appears to be worked around in the computer reseting the new sensor.  

1.  Does anyone remember seeing this dealer bulletin?

2. Is there a DIY application that has proven effective anyone can point me to?

I have way too much into this truck to give up on it now.  I was in the Eastern Sierra this last week-end and this was the first time this truck actually ever stalled outright. 

+_+_+_+_

Oh. and one more question?  I had my rear end completely rebuilt and when I picked it up the mech that did the work was not there but the other mechanic said he was told to tell me that he had to put a thickening agent into the diff to quiet it down.  Id never heard of this and it sound to me like anything like that would restrict lubing the axel bearings.  Anyone?

EasternSierraCQ

 

Edited November 30, 2021 by EasternSierraCQ

[richard wysong]

you need to do the idle relearn procedure. I have had to do it a couple of times on some vehicles. sounds like they didn't set the pinion depth correctly. never heard of a thickening agent. they used to use sawdust but I can't see any 1 doing that these days. if the rear end was rebuilt to spec it should be almost silent so they screwed something up

[shakenfake]

His throttle body is drive by cable. There is no idle relearn.

[richard wysong]

check the throttle cable for any breaks or kinks in the plastic, disconnect it from the throttle body and have sum1 help to make sure it moves free

[richard wysong]

there is an idle relearn to reset the IAC. look it up

[asilverblazer]

Vacuum leak at throttle body gasket?

Hose clamps tight on intake tube?

MAF sensor clean and connection good?

 

If the fluctuating idle only happened after messing with the throttle body, I'd inspect the installation of it.

 

Check engine light on? Codes?

[shakenfake]

14 minutes ago, richard wysong said:

there is an idle relearn to reset the IAC. look it up

I have never heard of that, I believe it's the press accelerator slightly for 5 seconds then turn off car or something like that.

 

Or just unhook the battery for an hour and I bet that fixes it.

[richard wysong]

I dont remember the procedure to be honest but I know there is 1.  if you have access to all data its there . when you adjust the stop screw for the throttle plate its a must or after doing a throttle body clean. the ecms memory tries to compensate for the difference in what its used to seeing from the TPS and causes the symptoms described

[dna9656]

I think what the mechanic put in there was a friction modifier for the positrack.  Posis sometimes use a slightly different lube or you can put an additive in.

That stuff with the T body is way over my head; I wish I knew more about that stuff, I've never had that kind of problem. i can tell you ALOT of those TSBs find there way onto the internet....

Doug

[richard wysong]

disconnecting the battery and touching the cables together may work

[Supreme Pizza]

For the rear end, I would just call the repair shop and ask them when the mechanic is there, so that you can call back again and talk to him. Don't give him any info - just ask questions. For instance, don't call him and say "was the thickening agent an additive for the LSD?" Instead, just call and say "What is a thickening agent". I would also drive the vehicle for an hour to heat up the diff. I would then drop the fluid and replace it with OEM recommended fluid. If it makes noise after that, then the mechanic did not do something properly, and is using improper fluids to hide the problem until the warranty expires. Also look for metal when the fluid drops.

 

As for the throttle body, I had a big problem with my rig and I could not find the cause. I noticed the problem not too long after cleaning the throttle body. It had no OBD2 codes, and I could not find the problem no matter how hard I tried. I found a brand new throttle body on eBay for $72, so I bought it. After installing the new throttle body - the problem vanished, and the rig has been running great ever since.

 

Hope some of this helps.

 

Have a good day.