Ok so I recently finished my cam and heads swap. Basically I got the LE2 heads with the 226/230 Cam. He also ported my intake. Anyway we got it running using a tune from pcmforless. It seemed fine for about the first 1000 miles. It would pull hard to the rev limiter. Then I was driving it one day and noticed it started spark knocking at about 6k. It did it every time for a while. Also for the my fuel system I'm running a walbro 255 with racetronix 37# injectors. So I figured my fuel system was fine. We put it on a dyno and sure enough it was leaning out. Thing is it was lean all the way through the rpm's. Even at cruising speed. So we figured it was the tune. I sent the tune back and they readjusted it using the a/f graphs from the dyno and sent it back. I took the car out and it's acting the exact same! What's even weirder? Sometimes it spark knocks and sometimes it doesn't. It doesn't seem to have a rhyme or reason either. Just random. We were thinking it could be my fuel pressure regulator. It's a stock '93 regulator with around 127k on it. Could that be the problem? Thanks

 

Have you check the pressure reading at the schader valve on the fuel rail???

 

Yea. Not sure exactly what the reading was, but I know it was "normal" but it tended to bounce around. It wouldn't even out until around 3k I think which apparently is not normal.