'01 Yukon Won't Idle when cold???

[kikbaks]

Howdy, folks! Got an '01 Yukon 4x4 w/113k on a 5.3ltr that won't idle after cold start.

We just moved to Idaho from Phoenix, AZ and the vehicle immediately started to act as if it has no "choke". After sitting all night in freezing temps, it quickly fires and revs to 1500rpm but soon drops to 1000, then to 500, then chugs until dead all within 30 seconds. The only way to keep it running is to feather the throttle around 1500rpm until warm enough to run on it's own. However, once warmed up, it runs great. Whatever it is, it's NOT trippin' the check engione light.

In hopes of fixing the problem, the following has been done:

New fuel pump
New fuel filter
New fuel pressure regulator
Cleaned K&N filter
Cleaned MAF
Cleaned throttle body, etc.
Full service oil change
New tank of premium w/Ethanol
Bottle of fuel injector cleaner

Some have mentioned the Idle Air Control Valve, Throttle Position Sensor, or vacuum leak. What do ya'll think?

Thanks in advance! Doug

 

[Coastie Kyle]

Sorry this has nothing to do with helping you, but where in Idaho did you move to?

 

[kikbaks]

My hometown, Idaho Falls. Been away ten years. Except the truck not running, it's nice to be back.

 

[Rwayne]

I think you've covered the stuff I would think it would be. I would think the iac failing would make it idle too high. idk. Does it idle fine after you've got it hot and restart it?

 

[kikbaks]

Does it idle fine after you've got it hot and restart it?

Yeah, it starts & runs perfectly after it's warmed up

 

[Rwayne]

ya thats weird.. :nonod:

 

[Coastie Kyle]

Idaho Falls is southern Idaho? I went to high school and Collage in Coeur D'Alene.

 

[JKmotorsports]

I know you mentioned that you cleaned the TB, but make sure the air passage in the upper left hand corner of the throttle body is clean as well. Gunk builds up in here, and if it's clogged or gunked it up it will also cause rough idling until it is warm.
Usually the IAC will cause it to idle rough whether cold or warm. The TPS would affect entire driveability issues.
A vacuum leak, if it is small enough, can cause your problem as well. It could be enough to cause the rough idle while cold, and then the heat after warm up can expand gaskets, parts, etc. and close off the leak until it's cold again.
Hope this helps. Good luck.

 

[kikbaks]

Well, got it scanned when starting and found an 02 sensor that was not switching causing it to run too rich and die. After replacement, I would say it's idling 50% better. The rpm is holding higher, but it is still rough and coughes when accelerating from a stop.

 

[Crazydefense32]

I have a house in Sun Valley, and have visited Idaho Falls, it a great place! Whenever I spend more than three weeks up there I always have my truck tuned to higher elevation, if you haven't done that already it might help! Good Luck! :Chevy:

 

[ronjeremy6]

out of curiousity, what is normal idle rpm?

 

[jey_]

Checked today cause I'm driving the Tahoe all day -
Starting it up first thing in the morning completely cold it sat at 1000 rpm
Warm idle seems to be like 600 rpm.
In Park of course, 5.3L.

 

[brodg]

Document ID# 1899786
2001 GMC Truck Yukon - 4WD


--------------------------------------------------------------------------------


Subject: Cold Engine Idle Misfire Or DTCs P0171 P0174 - keywords 4.8 5.3 6.0 air cold crack hesitate idle intermittent internal intake leak lean misfire miss P0171 P0174 P0300 power rough surge vacuum #PIP3232B - (02/07/2007)



Models: 2002-2005 Cadillac Escalade

1999-2005 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe, Trailblazer

1999-2005 GMC Savana, Sierra, Yukon

2003-2005 Hummer H2




--------------------------------------------------------------------------------

This PI was superseded to update parts information. Please discard PIP3232A.


--------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
99 through 05 GEN III truck engines may experience any of the following:

A cold rough idle that diminishes as the engine warms up.
Possible DTCS P0171, P0174, or P0300.
Random misfires at idle.
Recommendation/Instructions:
The intake gasket seals may be leaking around the intake ports, causing a lean condition. The intake gasket seals may leak around the bottom side of the port, making it a challenge to detect the vacuum leak. The technician may also notice lower than normal MAF readings if the intake seals are leaking.

If leaking intake gasket seals are found, replace the intake gaskets. During the repair be sure to use the current GMSPO part number for replacement intake gaskets. The current GMSPO part number for intake gaskets will have a teal green intake gasket seal. The old version of the intake gaskets were orange in color. Use only the teal green colored gaskets for a repair.
The intake plenum should also be checked for excessive warpage that may cause an uneven clamping pressure of the seal. If the plenum is found to be warped it will need to be replaced. Service Information states, "An intake manifold with warpage in excess of 3 mm (0.118 in) over a 200 mm (7.87 in) area should be replaced". Intake warpage is measured at the gasket sealing surfaces, and should be measured within a 200 mm (7.87 in) area. This measurement is across only two of the intake runner port openings. Measurements taken across the entire distance of all four intake runner ports will lead to unnecessary manifold replacements.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© Copyright General Motors Corporation. All Rights Reserved.


--------------------------------------------------------------------------------
Document ID# 1899786
2001 GMC Truck Yukon - 4WD

 

[kikbaks]

Thank you SO MUCH! A vacuum leak was the only thing that made sense because it runs perfect when warm and nobody could find the problem.

I spoke toooo early in my previous post. The truck is running worse than ever! The temps have dropped to 0deg at night and it has been terrible.

Definately gonna get it to the "stealer" next week. How much do you guess it will cost to replace the intake gasket? What if it needs a new plenum? Need to weigh my options as the motors gettin' old and I'm itchin' for a new 6.0 ~

Thanks again! Doug

 

[brodg]

i work for the stealer so i kinda take that as an insult you don't know the **** as techs we deal with so here it goes you are looking at around 3 hours labor plus parts really it isn't that hard it just looks intimidating once you get all the wiring disconnected the intake comes right off. all the ones i did never needed a new intake.

 

[kikbaks]

Well, I had the intake gaskets replaced yesterday and this morning it started and idled PERFECTLY!!!!!

So, THANK YOU tahoeforum.com!

Cost of intake gasket replacement was $250

 

[JKmotorsports]

Cool. Glad you got it fixed.

 

[brdnboy]

I have the same issue. the Hoe runs horrible when cold and shake and stutters, but once warm it runs great. This sounds very similar to my situation but before i spend $250 i want to make sure that is the issue. Is there any possible way it could be spark plugs or injectors or a dirty throttle body? I have cleaned the throttle body, but i just saw JK's post on making sure an area in top left is clear of any gunk. I did a thorough cleaning of the TB but did not focus on this area specifically. I am not doubting you kikbaks and i am glad i have a potential solution. By the way kikbaks was your yukon throwing any kind of code to indicate what was causing the issue or not? Could there be a leak anywhere else in the vacuum system? Also could i have a warped intake, or is it more likely just the gasket? What would cause warping of the intake? Just Heat? or something else?

Thanks everyone

 

[jcoppa]

I have a 2000 Tahoe 5.3 that has the same symptoms. Won't idle when cold. Need the feather the throttle. Starts and idles fine warm. The dealer cleaned the TB. I picked it up. Would not start at home. Got it back to the dealer. They have problems duplicating. I gave them the info on the bulletin posted here about the intake gasket. They say there is no issue with it. No vacuum leak. Fuel pump OK. IAC OK. O2 OK. MAF OK. They still have it. Checking to see if fuel is leaking back in to the cylinder(s). No codes. My wife won't drive it. I know if I pick it up it will act up again. Any thoughts on good next steps to direct the dealer to look at? Someone at work suggested the coil might not be working right when cold. Does that make sense? I'm very frustrated. Any insights would be appreciated. Thanks.

 

[brdnboy]

I have a 2000 Tahoe 5.3 that has the same symptoms. Won't idle when cold. Need the feather the throttle. Starts and idles fine warm. The dealer cleaned the TB. I picked it up. Would not start at home. Got it back to the dealer. They have problems duplicating. I gave them the info on the bulletin posted here about the intake gasket. They say there is no issue with it. No vacuum leak. Fuel pump OK. IAC OK. O2 OK. MAF OK. They still have it. Checking to see if fuel is leaking back in to the cylinder(s). No codes. My wife won't drive it. I know if I pick it up it will act up again. Any thoughts on good next steps to direct the dealer to look at? Someone at work suggested the coil might not be working right when cold. Does that make sense? I'm very frustrated. Any insights would be appreciated. Thanks.

I got my intake gasket replaced. Fixed the problem. I would think you have the same issue.