Car Idles Rough When Cold (sometimes)
Thread Starter
Teching In
Joined: Feb 2010
Posts: 13
Likes: 0
Car Idles Rough When Cold (sometimes) Hi I have a 2000 Camaro SS and I have noticed since about a year ago, anytime that it is cold enough (mostly november thru february) the car sometimes starts with a really horrible idle like it wants to turn off then accelerates by itself and just keeps that cycle on for a while. The lights and everything will dim and brighten along with how the idling of the car is behaving. Also when its doing this and I drive it and start slowing down at a stop light it starts idling really low and almost turns off. Any advice would be greatly appreciated! Thanks!
So is the engine surging then dropping rpm's immediately after by itself? Sounds like it *could* be a vacuum leak(intake leak etc) that seals as the engine gets warmer. On a cold start take a good listen to the engine bay to see if you can locate any whisling or hissing sounds. If a vacuum leak isn't the issue, then i'm not sure what it could be. Hopefully you can get to the bottom of the issue since it sounds like it would be very irritating lol.
Thread Starter
Teching In
Joined: Feb 2010
Posts: 13
Likes: 0
@wssix99- yes it is an automatic.
@camaro981289- i actually tried to clean all those parts too and no luck either.
@Mr M- thanks for da advice, ill take a look and see if i hear any whistling or hissing comin from the engine bay on another cold day.
@camaro981289- i actually tried to clean all those parts too and no luck either.
@Mr M- thanks for da advice, ill take a look and see if i hear any whistling or hissing comin from the engine bay on another cold day.
josemanss07 - I was thinking that this may be a sign of a torque converter problem, but if it happened last year too and didn't get worse over the summer, maybe that's not it. Does it always happen when you stop at intersections, or only when the car is cold? Do you notice a gas smell from the exhaust when this happens or notice a tendency for the car to backfire?
camaro981289 - I don't think yours is the same thing. Your car is possessed by the devil. ... or you may have a bad belt.
camaro981289 - I don't think yours is the same thing. Your car is possessed by the devil. ... or you may have a bad belt.
Trending Topics
Thread Starter
Teching In
Joined: Feb 2010
Posts: 13
Likes: 0
@wssix99- It just happens when starting the car (sometimes) in cold weather and for about 5-10 mins after when im driving and slow down or stop at intersections (temp meter indicating motor pretty cold still) i think there usually is a gas smell at times as well and dont think it backfires as well
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo Have you scanned for codes. That might tell you something. If you have access to a scan tool, you should check your IAT value and Coolant Temp values before you start the car. That might also give an indication.
If not, you may just try unplugging your IAT sensor. If that's it, the car should run better.
If not, you may just try unplugging your IAT sensor. If that's it, the car should run better.
Any remedy to this? My tahoe with a 5.3 is doing the same thing and throwing codes for a lean condition(170,171) in both cylinder banks. I've taken the same steps you have with the addition of running injector cleaner and replacing the fuel rail pulse regulator, if that's what it's called. I'm reading this may be a fuel filter problem, so that's the next thing I'll throw money at. Beyond that I'm in need of some help.
Anyone?
Anyone?
Yeah my friends porsche would idle and peak then drop peak then drop, he noticed it didnt do this when the ac was on though, turned out to be a vacuum leak, hope that helps..
Teching In
Joined: May 2010
Posts: 32
Likes: 0
Mine has the same issue. To try and fix it I have put in a new IAT, IAC and MAF, oh and new plugs and wires. I have even replaced the 1st new MAF because it was throwing codes. When it is in the mid 40s +/_ or below, my car does this. If I unplug the MAF, the car will idle fine, albeit a bit high till it warms up. Once it warms up, I plug the MAF back in and it runs great.
Above those temperatures it starts ok. I noticed the other day a bit of smoke in the engine bay, so I think exhaust gaskets may be on the agenda next.
I think I am going to name my car Money Pit!
Above those temperatures it starts ok. I noticed the other day a bit of smoke in the engine bay, so I think exhaust gaskets may be on the agenda next.
I think I am going to name my car Money Pit!
my car did the exact same thing on cold morning starts, but once it warmed up it would run an drive just fine. After trial an error i finally found the solution, the intake mainfold bolts just needed to be retorqued back to spec. The car has been fine the last 2 years in ANY cold temp. So give your intake manifold bolts a retighten.
jason
jason
Many of you guys who have these same symptoms and yet you have tried replacing so many parts.......you might want to think about getting a new PCM. Its what cured those symptoms for me, and nothing else I tried for two years did anything. The PCMs fry from the inside out alot of times, mine did. Also, after so many years with our cars....make sure the PCM-to-Block ground wire is tightened periodically....as they get loose they damage the PCM.
Open up the two top caps of your PCM and see if you have any pins that look dark in color and burnt. I found a couple on mine...got a new PCM and all symptoms were cured at one time. Purrs like a kitten...cold starts, hot starts, doesn't matter...idles perfect now. No surging, no attempts to stall out, nothing.
.
Open up the two top caps of your PCM and see if you have any pins that look dark in color and burnt. I found a couple on mine...got a new PCM and all symptoms were cured at one time. Purrs like a kitten...cold starts, hot starts, doesn't matter...idles perfect now. No surging, no attempts to stall out, nothing.
.
