test your evap system. theres info in the how to and faq sticky in the 4th gen section.

 

Thanks I will do that.

I also want to revisit the idea of weak spark. This morning it was cool out, but not as cold as it has been (37° ish). The car did not stall but idled very rough and around 400 RPM. It felt like plug wires were crossed. I gave it some gas and held it at 1500 RPM for about 20-30 sec and it cleared up and ran and idled fine... What in the ignition could cause this if the plugs look good and wires recently replaced? The previous owner replaced the opti about 5K miles before I bought it, and put an MSD coil in at that time. I have since put about 10K miles on it in my ownership.

 

I read through the EVAP testing stuff and it sounds like it could be an issue in the EVAP system... Wouldn't a leak or faulty valve throw a code? Or is that just OBDII that has that ability?

 

i had both go in mine and did not throw a code. do you know what opti went in?

 

I believe it was a GM or AC Delco unit. Nothing fancy like MSD.

 

so long as it wasnt a jegs summit or china junk.

 

Ok, I tested the EVAP system and everything is good. I found some crack rubber vacuum hoses but swapping them out made no difference. My next guess is the ICM. Since sometimes the car will idle rough for a couple seconds and then clear up, I am thinking maybe the ICM has something to do with cold starts?? The opti and coil were replaced before I bought it (the PO did not lie because the coil is a bright red MSD and the opti is cleaner than the rest of the engine). Plugs and wires look good, but I cannot tell if the ICM was done or not.

 

I am bringing this back for a couple reasons. I suspected the ICM was the reason for the rough idle, but did not buy one as it cleared up and I have not had an issue since Dec. Today I had a cranking but no start condition. I could hear the pump run and I had 40 psi static fuel pressure. I tested a plug wire for spark and had none. Since everything but the ICM was replaced before I bought the car (and looks new) I decided the issue was the ICM. I followed the steps to check that the opti and the PCM were sending the correct signal to the ICM and they were. Just for fun I hooked everything back up to see if it would start and it did. I replaced the ICM anyway since I had already bought one, and the one on the car looked old so I figured it wouldnt hurt.

After replacing the ICM I went to start the car and all it did was crank, no fire again... I double checked all my connections and everything was ok, then I tried starting it again and it fired right up. I drove it around to get it warm and then parked it again. Tried starting it 3 times and it started every time. All fuses and other connections in the ignition system look good. Could the ICM have intermitten problems? Did the PCM need time to "reset" or something causing it not to start right after replacing the ICM?

 

sure sounds like a bad wire or connector.