I finished my head/cam swap. 233/239 from cmotorsports & some race ported 195cc AFR LT4 heads. I installed the new PCM from PCMforless and everything was working great for about a day. My friend chino_man279 drove it - it drove wonderfully. Tires went up in smoke through 1st gear and the tail started coming around through second. Chirps the tires into third. Then I drove the car into town, did a few full throttle accelerations . . . Now, my car runs like A$$. It was running really smooth and now it is "chugging" along pretty hard. Only thing is, there doesn't seem to be much power loss. We're pretty sure it is misfiring - I have a blinking SES light - BUT - when I plug my code scanner it, it reads "PASS, no codes returned." Go figure. I figure the guys from PCMforless deleted some codes because of the size of my cam. Not really sure, though. When we finally did get a code, it was a bad O2 sensor on bank two. We replaced the sensor and it still runs bad. My new theory is that the valves might need to be adjusted. Has anyone else had trouble with COMP-R lifters, adjusting non-self aligning rockers and misfiring? We pulled the valve covers b/c you could hear some faint ticking and some of the rockers were loose (should I be using lock-tite on the rocker studs?). We re-adjusted them, but it still runs like crap. HELP!!!

 

Had another thought: could I have blown piston rings? I'm going on about 93000 miles on a stock bottom end. I figure it's possible, but here's my argument against it: I am running slightly less than stock compression - stock combustion chambers are 56cc. When I was done polishing the AFR heads, we cc'd the combustion chambers and they came out to 58cc. If I understand correctly, blown piston rings are the result of high compression (11:1 or more) or nitrous. I don't run nitrous or have real high compression. Granted, my dynamic compression is probably a lot higher at higher RPM's than it used to be, but would that blow out the rings?