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.