ecksz28

iTrader: (5)

Since about a week ago, my car has developed a misfire. It doesn't misfire immediately after starting, but it takes a while for the engine to warm up -- maybe 10-20 minutes. After that it starts misfiring and then worsens little by little. If you wait long enough, the Service Engine Soon (SES) light comes on. At that exact moment when the light comes on, both cooling fans kick on high, which I thought was strange. When this happens, the temperature gauge reads slightly over 160 -- cooling doesn't seem to be an issue.

I attempted to get my car scanned after it through a code. However, I ran into a problem -- my PCM is a Madz28 OBD2 to OBD1 conversion -- basically I'm running an OBD1 PCM with the OBD2 connection inside the car. When I tried to have it scanned, it said the link failed.

After this, I stuck the original, OBD2 un-tuned PCM in and let the problem repeat itself, except the fans didn't come on. I had it scanned and it told me the O2 sensors were bad. But then I remembered that I'm missing rear O2 sensors due to my headers, so the stock PCM would throw that code anyway. So when I had the stock PCM in, I don't believe it ever threw the code for the misfire since the cooling fans never kicked on. (Maybe the cooling fan part could be related to having an OBD1 PCM? Maybe not?)

Does anyone have any idea what my problem would/could be? I had the injectors cleaned/new plugs/new wires/new optispark about 30,000 miles ago, so it would suprise me if any of those were the culprit. I've already looked at the wires, all of them seem fine.

I'm stumped for the moment... looking for some good advice on what to do next...

Thanks for any help in advance.

ecksz28

iTrader: (5)

Looks like it is actually going to be an O2 sensor... I put the stock PCM in again, drove it around forever until it started misfiring pretty bad. The SES light even stared blinking so I had it scanned again. It gave another code, 174 I believe, indicating again that the passenger side O2 is bad. Going to change it out tonight and see if that fixes the problem...

ecksz28

iTrader: (5)

Update: Put in another passenger side 02. The problem only seemed worse so I put the old one back in. It didn't help it any -- it was backfiring terribly. So then I was going with the backup plan of putting in the OBD1 PCM and taking it to AutoZone to get it scanned. They had no way of scanning an OBD1 with an OBD2 connector inside, even though that's how 95 Camaors are stock. How would I go about getting this scanned?

I'm leaning towards ICM or optispark.... optispark... ugh.

ecksz28

iTrader: (5)

So I finally got a cable and was able to scan my car -- still saying the right O2 sensor is lean. I checked the voltage and it is a constant .004 volts. Replacing the O2 sensor did not fix the problem. Is it some wiring issue somewhere or could it still be the optispark?