First let me start off with I'm a gear head but I seem to be having a really hard time with this problem.
I replaced my cams with crower stage 2 3/4 race cams on my 420a. I also replaced the springs with the recommendations from the cam shaft manufacturer. Everything is installed and the timing is set correctly (verified).
The problem I am having is that I can start the car and go for a drive. Within about 20-30 min of driving or just running I lose cylinders #1 and #2. I verified this by pulling spark plugs and saw two were cleaner than the others. Then the car becomes I drivable obviously.
The next day I decide to start it to see if I have anything still going one and the car starts great and runs for the same timeframe then I lose 2 cylinders again. This is the same way for about 4 days now. It will run then start to fail.
Today I noticed a check engine light and decided to get a code reader to see if I have a sensor fault. The only code I had was for the fuel tank pressure (gas cap). So I cleared it and the car still ran like crap after the first 30 min of running. I have no other fault codes. I'm not even getting a misfire code.
Spark and fuel must be good becuase it did run normal for the first 30 min.
I'm at a lose and have no idea where to go from here. Have any of y'all seen this problem before or could give me suggestions? Thanks guys.
#138703, "RE: I need some help. " In response to Reply # 0
Originally posted by 420grenAde Spark and fuel must be good becuase it did run normal for the first 30 min.
Not necessarily. Fuel pumps can drop pressure after running for a while when they first start to go bad. Without a way to monitor fuel pressure, it's tough to tell. Ignition coils sometimes do the same thing, though I'd think you'd have a misfire light for that. You can test your coil with a multimeter. I think someone made a youtube video showing how to test one for the 420a at some point. I'd check over your wires to make sure you're not arcing, test your coil, and do a compression and or leak down test for peace of mind. After that, I'd get a fuel pressure tester and watch your fuel pressure.
