i have a vz ss ls1 233/242 110lsa and now have a misfire i have seems to be on idle and partial throttle upto about 4000rpm if i accelerate it feels like a vibration through the driveline it doesnt completely drop out any cylinders but i carnt put my finger on it. it seems to be worse when the engine is warm and but it comes and goes while driving. the mixtures are fine but the plugs are black except for 2 cylinders show normal. i have changed the plugs tried a smaller gap also changed leads and checked all conectors coils appear to be ok and injectors and fuel system are definatly good. im not getting any misfire codes have also tried a case relearn. the engine is healthy all cylinders are 180psi and i have between 4-7% cylinder leakage.
i have tried adding and taking fuel with the scan tool with no luck seems to get worse the leaner it runs and rich makes no difference added timing it makes it worse and taking timing does nothing if i hold the revs up in neutral i can here the misfire very badly. does anyone have any ideas what this problem could be i am at the point of giving up on this car as i am forever spending money on it and havent even had the chance to enjoy it yet