Longo

Ive got an 87 GT 5.0. The motor is freshly rebuilt with an E303 cam, 351 heads, 25# injectors, ported intake and a paxton supercharger. Because the car did not come with a mass air flow sensor, one was added. My problem is the car does not run good. It wont idle and spits and sputters alot. Ive tried many things but cant figure it out. Im wondering if the computer is not going to be right anymore because of all the mods? Should it be reprogrammed? What else could it be? Vacuum leak, a bad module, pluged fuel filter?

TheGmKiller331

I belive you can and probably should have a new chip burnt for your specific setup.Im not an EFI guy im strictly carbs.Wait a few one of the EFI gurus will help you out.

BLKSTANG9879

You might want to look into a MSD 6AL ingition. Your supposed to have one with a Supercharger. You not gettin enough spark. For the amount of air/fuel. Plus you might what to think about a 36lb. injector. 24s are to small.

grabbem88

WHAT COMPUTER DO YOU HAVE IN IT? DID YOU CONVERT IT?

vfast

well first there is no 25# if they are blue their 24# what psi our you producing?...you should invest in a twEECer or PMS, it will take care of the idle and rich issues...your computer is chasing..I bet the idle is up and down hunting... do you have a FMU?...if no fmu than 30's might be the ticket....but the computer at this point has issues
does this car have a blow off valve? this is a MUST!
blkstang .is right you need a good ignition with a timing retard ****