1994 LT1 conv. Engine stumbles and idle surges after warmup
01-09-2012, 07:24 PM
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1994 LT1 conv. Engine stumbles and idle surges after warmup
Hey all. I'm new to this forum, although I've checked out the posts now and then to trouble shoot my problem.
Here's the problem. When stopped at idle, my engine stumbles, misses and surges erradically from about 600 RPM to 1200 or so after I've driven it for awhile and it's warmed up. The oil temp usually reads about 195 or so and the water temp is usually about 210 or so. The surging is so bad sometimes that I have to put my foot on the brake pretty hard to keep it from moving forward, but it doesn't do it that bad all the time! It sounds like I'm challenging the guy next to me at a light, the way it revs up and surges. After I take off, it takes off pretty well and the problem seems to disappear. It occasionally coughs or misses slightly when giving it full throttle, but usually it's pretty smooth.
I've had the spark plugs and wires changed, cleaned the MAF sensor, cleaned the IAC valve, replaced the fuel filter and checked and cleaned the PCV valve, checked for vacuum leaks and it still does it. There was no "check engine light" and there still isn't. My mechanics told me they did not find any codes for the o2 sensors or anything else not funcitioning.
I've scoured the internet and have seen other people with similar problems but no solid identifiable reason or solution for why this happens. Some people have replaced the EGR valve, found vacuum leaks, replaced the fuel pressure regulator, or replaced the O2 sensors, etc, but I don't want to just start replacing parts without knowing what is actually causing this. Why does this happen!??
It's driving me nuts! Help!!
(sorry, just realized that this is posted in the wrong thread area. Will move)
Here's the problem. When stopped at idle, my engine stumbles, misses and surges erradically from about 600 RPM to 1200 or so after I've driven it for awhile and it's warmed up. The oil temp usually reads about 195 or so and the water temp is usually about 210 or so. The surging is so bad sometimes that I have to put my foot on the brake pretty hard to keep it from moving forward, but it doesn't do it that bad all the time! It sounds like I'm challenging the guy next to me at a light, the way it revs up and surges. After I take off, it takes off pretty well and the problem seems to disappear. It occasionally coughs or misses slightly when giving it full throttle, but usually it's pretty smooth.
I've had the spark plugs and wires changed, cleaned the MAF sensor, cleaned the IAC valve, replaced the fuel filter and checked and cleaned the PCV valve, checked for vacuum leaks and it still does it. There was no "check engine light" and there still isn't. My mechanics told me they did not find any codes for the o2 sensors or anything else not funcitioning.
I've scoured the internet and have seen other people with similar problems but no solid identifiable reason or solution for why this happens. Some people have replaced the EGR valve, found vacuum leaks, replaced the fuel pressure regulator, or replaced the O2 sensors, etc, but I don't want to just start replacing parts without knowing what is actually causing this. Why does this happen!??
It's driving me nuts! Help!!
(sorry, just realized that this is posted in the wrong thread area. Will move)
Last edited by AZBlackC4; 01-09-2012 at 07:33 PM. Reason: Wrong thread
01-09-2012, 07:33 PM
#2
Team Owner
Welcome to the Forum!!!!! You need to post your question(s) in the C4 Forum where the members who own and know them best will be able to help you. Good luck. 
http://forums.corvetteforum.com/c4-g...discussion-34/
http://forums.corvetteforum.com/c4-g...discussion-34/
