Rough Idle When Cold Outside Until Engine Warms Up

[xrbeav]

I have searched for a solution and thought I had one. My 2002 Suburban idles very rough/erratic when the temperature outisde is cold(i.e. 32 degrees or below). I can hold the idle up, 1500 rpm, via the peddle and it will be fine. But when I let off, it will almost die and then idle varies between 700 to almost stalling. Once the engine is warmed up, it will idle fine. I have taken of the throttle body and cleaned it very thoroughly and also replaced the Idle Control Actuator on the side of the throttle body. Where do I go next? Since it is about cold weather time here, I need to get this fixed.

[Tsmith]

Have you checked the coolant temperature sensor?

[REV353]

I'd do the basic. Injector cleaner and fuel filter. Or check for a leaky gasket or o-ring

[xrbeav]

I have never heard of the coolant temp sensor. I will check the Haynes maual I have to find it. The problem seems to be related to ambient air temp. And like I said, if I hold the throttle open slightly, it will idle smooth and fine. It seems like the high idle for colder weather is not kicking on. I don't know how that is controled. I thought it was the Idle Control Actuator, but changing that did not affect things. My other thought is MAF Sensor. I just hate to keep throwing money at it in hopes of fixing it. The Idle Control Acutator cost $175. Not a cheap piece by any means.

 

Thanks for looking and suggestions!

[xrbeav]

Forgot to add, this started happening last winter, when summer came around it would start totally fine because the temp was warm outside. Now that is is cooler, it is reoccuring.

 

I know, I should have addressed this before now. Can we say procrastination?

[txab]

Sounds like your truck is not running in open loop operation when it's cold. You're getting no codes?

[xrbeav]

No, there are no codes or error messages. I have had it checked a couple of times.

[xrbeav]

Bump... any other thoughts. Thanks.

[staffman]

Any progress in figuring this one out xrbeav? I have the exact same problem and cant seem to fix it. I own a 99 Sierra. I might try to clean the E.G.R. valve to get rid of carbon deposits that might be blocking the spindle. Other than that, I'm at a loss? My CEL came on and it threw an Idle Control Actuator code, but I'm hesitant to replaced it, since it didn't work for you.

[Silverado4x4]

He most likely fixed it by now as this post is over 2 years old.

[rkr]

I had similar symptoms when my intake gaskets were leaking. New good quality gaskets meant for sligthly warped manifold fixed it.

[nluchau]

I have the same exact situation. Now that its colder out in the morning the last two mornings my 02 Silverado 5.3 has erratic idle until warm and it seems to want to die unless I hold the accelerator slightly. I have NO CEL and no codes stores in the computer. I had the fuel pump and filter replaced this summer.

 

It only does it when its cold. Once it warms up I have no issues at all. I am thinking intake gasket leaking but I was also told the MAF sensor could be causing it. If it was the MAF sensor wouldn't it occur all the time? Warm or cold?

[TJay74]

Reason other person suggested the coolant sensor is that sensor is what controls the ECM going from Open loop to Closed loop, it is it reporting the coolant temp incorrectly it can take longer to transition from one mode to the other.

[nluchau]

I brought my truck in to my mechanic last night and this morning he went to start it so he could see what it does when its cold. He called me up and told me he could hear a hissing around the intake and that one gasket was gone, his computers found misses on all 8 cylinders due to the increased air due to the air leak. He told me GM came out with a newer thicker gasket set to resolve this issue.

 

I'll get the truck tonight and report back tomorrow if this solves my issue. Hoping for the best here.

[nluchau]

Outside temp was 40 this morning and it idled like a champ from a cold start. New intake gaskets resolved!