Originally Posted by mazayu
Ok I bought a 99 GT to replace mine that was wrecked. Car has forged short block. Stage 3 patriot head and cams. Vortec v2 at 10 psi. Now my question. Car has a mis. Runs super rich at idle and seems to lean out at higher rpm. I've check filter. Cleaned maf. IAC. Tps. COP's. Plugs. Checked vac lines. Basicaly everything I've checked now. Now if u slowly build rpms to 4k n hammer it car runs fine no mis. But hammer it from a dig will mis bad. Also not throwing codes. Any ideas would be great. Wanted to solve this issue before putting my Kenne bell on it. Thanks.
---------- Post added at 07:10 PM ---------- Previous post was at 07:07 PM ----------
Oh BTW car ran great when the guy I bought it from got it. Has sat in a garage for 4 plus months without being started.
The car needs to be professionally tuned first and foremost. Does your car have a fmu or custom tune? What kind of plugs?