rough idle after it warms up
Thread Starter
Racer
Joined: Nov 2012
Posts: 263
Likes: 3
From: Philadelphia Pa
rough idle after it warms up
After I take it for a ride and warm it up. I shut it off for around 20 minutes or so. Then start it, it runs rough to the point that it wants to stall. I have to give a little gas to keep it at a higher idle to keep it from stalling. It feels like it's missing at that time. After a minute, it clears up and then it's fine. What could it be ??? 1994 corvette
Last edited by Erniep; Apr 9, 2013 at 09:34 PM.
Thread Starter
Racer
Joined: Nov 2012
Posts: 263
Likes: 3
From: Philadelphia Pa
After I take it for a ride and warm it up. I shut it off for around 20 minutes or so. Then start it, it runs rough to the point that it wants to stall. I have to give a little gas to keep it at a higher idle to keep it from stalling. It feels like it's missing at that time. After a minute, it clears up and then it's fine. What could it be ??? 1994 corvette
Thread Starter
Racer
Joined: Nov 2012
Posts: 263
Likes: 3
From: Philadelphia Pa
I was hoping it was a sensor somewhere. I wasn't ready to change the injectors. Thanks for the great news. Lol They are on my list too. But I was hoping to do a few other things first.
Racer
Joined: Jun 2012
Posts: 343
Likes: 9
From: Long Beach Ca,
Try a fuel filter first. My 85 did the same thing the other morning. Ran fine on start up, went to the station to fill up, had a bad miss when I left. Cleared up a bit but not completely. Change the fuel filter when I got home, fixed
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Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
There are a few possibilities here.
When it goes into the the rough idle, does it run properly when driving, or when given gas? If so, I might suspect the Idle Air Control is sticking. It is located on the passenger side of the throttle body. You can try taking it out, and hitting it with some brake cleaner.
Check the fuel pressure regulator.
Then check fuel pressure during the event.
Clogged EGR valve is another possibility? LT4 has no egr so maybe someone else can help there. But I had a Ford 4.6 awhile back with a clogged egr.
If it doesn't run smooth at driving rpms, and/or misses continually when at temp, it could be the ICM.
When it goes into the the rough idle, does it run properly when driving, or when given gas? If so, I might suspect the Idle Air Control is sticking. It is located on the passenger side of the throttle body. You can try taking it out, and hitting it with some brake cleaner.
Check the fuel pressure regulator.
Then check fuel pressure during the event.
Clogged EGR valve is another possibility? LT4 has no egr so maybe someone else can help there. But I had a Ford 4.6 awhile back with a clogged egr.
If it doesn't run smooth at driving rpms, and/or misses continually when at temp, it could be the ICM.
Thread Starter
Racer
Joined: Nov 2012
Posts: 263
Likes: 3
From: Philadelphia Pa
It has been doing this for only a few days so I'm not sure if it's going to get worse. But as of right now, it only does it for about a minute after a warm start. Then it clears up. But I will check out the few things that you mentioned. Thanks..
Thread Starter
Racer
Joined: Nov 2012
Posts: 263
Likes: 3
From: Philadelphia Pa
I had it out all day yesterday and I had no problems. Shut it off, waited about a half hour. Then started it and had no rough idle. It was cool yesterday, only in the 60s. When I was having problems, it was close to 80. So I'm guessing it is some kind of fuel vapor lock. I bought fuel line insulating wrap. So I will see if that helps the next time it warms up..
