Cold Start/idle Issue

Firntface · February 19, 2008

I have a 2002 Silverado 2500 HD 6.0L (85K mi), im having a problem when I start the truck cold. The truck starts fine revs up to about 15/1600 rpm and then nosedives to 2/300 rpm and almost stalls out(sometimes it does stall out). If I keep my foot on the pedal I can stop it from "nosediving" if I keep the rpms at around 2000 (I heard its bad to rev engine that high at cold start?) . This only happens in cold weather, I'd say below 45 F . I started having issues at the end of last winter, replaced plugs and wires but the start of this winter problem resumed with the cold weather. Another thing that may be related is when I put the truck in drive when its cold it will accelerate totally on its own up to 30mph at that point I run out of room in my neighborhood to let it keep accelerating... any help would be appreciated, thanks...

SKYrado03 · February 19, 2008

I have a 2002 Silverado 2500 HD 6.0L (85K mi), im having a problem when I start the truck cold. The truck starts fine revs up to about 15/1600 rpm and then nosedives to 2/300 rpm and almost stalls out(sometimes it does stall out). If I keep my foot on the pedal I can stop it from "nosediving" if I keep the rpms at around 2000 (I heard its bad to rev engine that high at cold start?) . This only happens in cold weather, I'd say below 45 F . I started having issues at the end of last winter, replaced plugs and wires but the start of this winter problem resumed with the cold weather. Another thing that may be related is when I put the truck in drive when its cold it will accelerate totally on its own up to 30mph at that point I run out of room in my neighborhood to let it keep accelerating... any help would be appreciated, thanks...

First of all...Welcome to the forum.

My first thought would be sensor...Like a throttle position snsr.

All my TPS's gave me problems at cold start, rough idle, but I never had one take off on me..

Have you/could you try to get a trouble code reading? That would help.

I wouldn't worry too much about 'cold start' until it got to 20° and below F° for at least 2-3 days...How's your oil?

Firntface · February 20, 2008

thanks for the reply !! No, I havent had a trouble code reading, where can I get one (advanced auto parts) or do I have to pay at a dealership?? As for the oil, I make sure to stay on top of it because i lose about a quart every 3k miles... thanks again for the reply, ill see about that trouble code reading tomorrow...

stublejumper · February 20, 2008

thanks for the reply !! No, I havent had a trouble code reading, where can I get one (advanced auto parts) or do I have to pay at a dealership?? As for the oil, I make sure to stay on top of it because i lose about a quart every 3k miles... thanks again for the reply, ill see about that trouble code reading tomorrow...

Remove your idle control adjuator (spelling not strong point) its on the drive side off the throtle body and spray a little wd-40 or any penitrating oil in put it back on start the truck just make sure you hold on to it and just tip it up enough to clean it a new is about 150 canadian

SKYrado03 · February 20, 2008

thanks for the reply !! No, I havent had a trouble code reading, where can I get one (advanced auto parts) or do I have to pay at a dealership?? As for the oil, I make sure to stay on top of it because i lose about a quart every 3k miles... thanks again for the reply, ill see about that trouble code reading tomorrow...

Your welcome!,

Advance would be one place to try, any of those big box parts stores should be able to get you a reading. Although, I would think a place like PEP BOYS might charge you.

Check around by phone, saves fuel!, see who'll do it free or charge, then go and get several opinions/readings

The local dealership might charge you, are you on good terms with them?

I remember a $50 service charge to read one.

Even where you take your vehicle’s to a local garage, for repairs or inspection.

If you've done business with the parts store, dealership or garage, they'd be less likely to charge.

And don't jump at the first offer, all these businesses want your business; Be up front with them, let them know your looking around for "Price and Availability" at this time. Explain the problem, and that you would like the trk scanned for trouble codes.

BTW, a qt. every 3k seems like a lot....Is it leaking or burning?

Gotta go to work now, I'll check back around 5am est.

SKYrado03 · February 20, 2008

thanks for the reply !! No, I havent had a trouble code reading, where can I get one (advanced auto parts) or do I have to pay at a dealership?? As for the oil, I make sure to stay on top of it because i lose about a quart every 3k miles... thanks again for the reply, ill see about that trouble code reading tomorrow...

Remove your idle control adjuator (spelling not strong point) its on the drive side off the throtle body and spray a little wd-40 or any penitrating oil in put it back on start the truck just make sure you hold on to it and just tip it up enough to clean it a new is about 150 canadian

Sounds like a man of experience!

Firntface · February 20, 2008

From what i've read here my best guess at the culprit is the IAC (Idle Air Control) Valve, im gonna play with it tomorrow and see if I can clean it or just replace it and then see what happens... thanks alot for everyones feedback but it'll probably be thursday when im able to get the results as the symptom only appears when the truck has been sitting for a while... as for the oil issue, I tow a dual axle trailer with 3 mowers on it about 8-9 months of the year so the engine really works hard in those dog days of summer, it doesnt burn as much now that im just in the plowing season and dont use it as often or hard... I just assumed that over the years as an engine ages it burns a little oil... do you think its something I should check out?? thanks again everyone

SKYrado03 · February 20, 2008

From what i've read here my best guess at the culprit is the IAC (Idle Air Control) Valve, im gonna play with it tomorrow and see if I can clean it or just replace it and then see what happens... thanks alot for everyones feedback but it'll probably be thursday when im able to get the results as the symptom only appears when the truck has been sitting for a while...

as for the oil issue, I tow a dual axle trailer with 3 mowers on it about 8-9 months of the year so the engine really works hard in those dog days of summer, it doesnt burn as much now that im just in the plowing season and dont use it as often or hard... I just assumed that over the years as an engine ages it burns a little oil... do you think its something I should check out?? thanks again everyone

Well……….. You could have compression readings taken on each cylinder, an go from there.

Fortune50 · February 20, 2008

...BTW, a qt. every 3k seems like a lot....Is it leaking or burning?...

Well mine burns a qt. every 1200 miles . I'm at 130K on my 6.0. Runs like a champ though.

I'd be thrilled w/ 3K.....

SKYrado03 · February 20, 2008

...BTW, a qt. every 3k seems like a lot....Is it leaking or burning?...

Well mine burns a qt. every 1200 miles . I'm at 130K on my 6.0. Runs like a champ though.

I'd be thrilled w/ 3K.....

I guess I'm spoiled then, my 4.8L 03 with 30K, and 10 oil changes doesn't use a drop so far...KOW, (knock on wood)

I'm back to running like a champ, since I've stopped using +85 (without my knowledge) and went back to 87.

Firntface · February 21, 2008

...BTW, a qt. every 3k seems like a lot....Is it leaking or burning?...

Well mine burns a qt. every 1200 miles . I'm at 130K on my 6.0. Runs like a champ though.

I'd be thrilled w/ 3K.....

WOW! thats so bad its good, you dont even have to change the oil....

heres my update so far; removed the IAC, wasnt that dirty but there was some grime on it, sprayed it, cleaned it up with a wire brush and put it back in, looks like ill be plowing tonight so Ill find out whether or not it had any effect on my cold start/idle....