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1990 Corsica Rough Idle


ktrabue2004
01-12-2005, 09:14 PM
I have a 1990 Chevy Corsica 2.2L that idles extremely rough. It does it in P, N, & D. I recently replaced the plugs, wires, pcv, and icv, but nothing improved. Does anyone know whats going on or have any sugestions?

jsgold
01-12-2005, 09:55 PM
When you say ICV I assume you mean the AIC (air intake control). Usually that gets dirty and causes poor a poor idle. You probably need to check for computer trouble codes first. that can possibly rule out some items such as sensors. Check your vacuum lines, and the air filter intake hose for cracks, splits etc. If you have a REAL bad idle it is possible one of your coil packs has failed. real common problem. Yours should have two coil packs which each controls two cylinders. Possible one is bad. Check all four cylinders for firing. The ignition modules (the flat assy under the coils) can go bad, but these usually cause stalls and hard starts. My bet is a coil pack. Can buy them individually if needed. About only other thing would be EGR valve, but that would show up on your computer code check.

ktrabue2004
01-13-2005, 04:21 PM
Ahh, so if it were the coil packs....
Would that cause my battery light to flash during acceleration and higher speeds? That is another problem that I have recently noticed. When I am accelerating or am cruising at high speeds and then let off the gas, the battery light flashes like there is a short of some sort. So the car would continue to run if a coil pack was bad, or do you think it is going bad? Also, I have had the computer scanned and nothing wrong was found. ($80 down the drain) Thanks for your response.

jsgold
01-13-2005, 04:54 PM
Sounds like two problems. Battery light should never flash, unless voltage is dropping. yes, the car would run on a bad coil pack, as each controls 2 cylinders and it may just be one that is missing. there is a test for them I will try to find, but if it is a BAD miss, a coil pack is a good possibility. get a multimeter and see what the battery reads with engine off, and with it on. Battery should read 12+ volts without engine running and 13-14 volts running. If your alternator is failing (another common thing on Corsicas) you may see little increase in voltage, or even a decrease. Do this first. If oK, you may have a short, which could be a pain to find. Check every exposed wire you can find for cuts, loose connections etc. if voltage is OK. As for the miss, if you have verified ignition module Ok, cleaned AIC (or replaced), made sure your fuel filter, air filter, plugs, and wires are Ok, you pretty much have the coils, the main ECM, and EGR valves left. I assume your check engine light does NOT come on during driving? Also, make sure your intake rubber assy is not cut (air filter assy) or that can cause a little problem. I will look at how to test the coils, but you may have to remove them and use a meter. A shop can measure the voltage easily, but will cost.

ktrabue2004
01-15-2005, 09:07 PM
Hey, I was thinking earlier today, could it be a clogged cat? The car is 15 years old, that could be the orig one. Would that cause it to not have a free flowing exaust and maybe vibrate. I would also like to clear up the severety of the vibration; it is not niticably vibrating from the outside of the vehicle, the dash and interior of the vehicle are the major problems. And about the bat light, could that be a slipping belt? Ill do some more researching, thanks for your help.

jsgold
01-15-2005, 09:25 PM
Could be. Mine is origonal (91 model) with 169K. If yours is clogged it would hurt performance. As for the battery light, mine has had either 3 or 4 alternators since I've owned it. may check your voltage or have it checked at Advance Auto for free....

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