[muskratdav]

i recently installed a procharger system on my 97 cobra has a 10 lb pulley 255 lph in tank pump with a inline 255 also. took the car, and had a friend install 42 lb injectors and a 90 lightning mass air put the car on the dyno and it started breaking up around 4200 rpm we changed the plug wires , coil packs and the plugs all while on the dyno nothing helped also plugs gapped at 30 . could it possibly be the imrc plates sticking? or possibly a bad injector? the car ran fine before i took it to him to put the injectors and mass air on, had stock mass air and injectors then but now that the injectors and mass air has been changed its got a slight miss . at pt throttle around 1300 or so it has a slight skip in it but once it idles down it smoothes out fine.

[limp1969]

is the maf set for 42lb injectors?

[yfz162]

Yes, make sure the MAF is calibrated for the injectors. I just had my cobra tuned with the same MAF and injector size. My tuner got them calibrated before doing any dyno pulls. Just because the person you bought them from says they are calibrated doesn't mean they are! Once my tuner got that figured out the rest was cake. You might open the plug gap to 33-35 also. What plugs and heat range are you running??

[muskratdav]

the plugs are ngk tr6 . the guy that installed the inj,and mass air tuned my car for the mass air and injectors before going to the dyno the problem was he had cut the rev limiter back to 4000 rpm until we put it on the dyno to make sure the air fuel was correct air fuel was dead on just couldnt get it to smooth out plug gap is set on 30 thousands might help to up it to 35 . the first 2 dyno pulls were ok didnt miss at all then there after it started . set the timing and everything back like the first 2 runs missed again also.