Ever since the temperatures have been getting cold here in michigan, blew 30 degrees, my truck is having problems idleing on first startup in the morning. These past few days where it has been getting in the 20's, it wants to die off. When i start the truck up, it will rev itself up to 1500 or so but it will just drop after a few second down to around 500 and just struggle to stay alive. Even if i give it a little gas to bring the idle back up, it just falls back on its face again. It will do this for atleast a few minutes if not longer if the truck just sat there.

I have read through some posts and in the morning i will be cleaning the IAC valve. I read that this can get dirty from carbon? real easy and cause problems. Guys have suggested clean the tb while im in there, i will probably do this too. While i am cleaning this, what other things should i do to make sure everything is ok, or up to snuff?? I want to first make sure all parts are good before i go any further.

The mods i have are just bolt ons.... intake, short headers, and exhaust on a 4.8l truck. I do not have a tune for it so i know this could also have a factor. Any suggestions will help!!

 

intake gaskets will solve your problem.

 

your battery is on it's way out. guaranteed.

 

VERY good point. I'd check that first.

 

hmmm.... i read that in one of the posts about someone having an issue with running rough. I have a red top that needs to go in.... thatll be my first thing to do then!!

 

anyone else with suggestions?? for the IAC valve.... is it the top sensor on the driver side of the tb or the bottom sensor??

 

Did you put the new battery in yet?

Trust me when I say it's the battery. I had absolutely identical symptoms in 2006 when my OEM delco 6 year battery was on its way out. Once it got cold it struggled to idle and the truck kept trying to raise the idle to fight it. Eventually I had to get towed and had a new batt put in. Problem solved.

 

I put my red top in and yes, it did help. It held the idle up a little better and stated to come down to normal rpm but then it would start to die again. But if i tapped the gas peddle the rpm would come back up and hold longer but would still fall. Maybe its just a different morning that it is idleing better but it still struggles to keep any rpm.

 

sounds like what they said in the first post with the intake gaskets, you may have a vacuum. leak.

 

well.... i talked with a local performance guy while i was picking up old mufflers and he said it probably had to do with the IAC so i picked up some tb cleaner and cleaned off the IAC. This thing had a thick layer of black sut or whatever you want to call it on the end of it. Cleaned that off and took my intake off and cleaned the tb out which was pretty black on the inside. started it up and it held idle pretty alright. I guess the real test will be a new morning start.

If i also have a vacuum leak, any ideas on where i should start looking??