P1SC Stage II sputter/misfire

I just installed an ATI into a friends 96 stock stang. It worked great when he left my garage and on his way home it started sputtering/missing when he accelerates above 2000-2500. So the first thing we did is check the plugs AGAIN and the wires. We even swaped wires AND took the blower out of the loop and it sitll does it. The car WITHOUT the blower doesnt want to run right after about 2000rpm's. We even disconected the inline pump and installed his aftermarket chip that was burned for the combinaton. The car STILL ran like it was misfiring or studdering under SLIGHT acceleration. When it is cold the problem is not there....but as soon as it is running and temp is normal operation, it sputters/misses/misfires. At one time we even made the engine check light come on at 1 sec intervals indicating a missfire. Now here is my question. the only thin that we have left to turn back to the original start point before the s/c install is the NEW plugs. Has anyone ever run into this problem before? Thought it was detonating but it does it now WITHOUT the blower even running. Any input, cause we spent 15 hours and he spent 4500 on the products.

Check all the PLUGS....Run the car for a while and check them. The EXACT same thing happened to me, it turned out I had a little hole in the #4 piston. Enough oil will get by it if you let it idle for a while that it will show on the plug. On mine, #4 wasn't making enough compression and it misfired, along with a sooty residue on the plug. I really hope this is not the case for your friend :( . If that is not the case, swap the old plugs back in, you may have bought a new plug that was faulty. :mad: Good luck.

try a set of new plugs, make sure contacts for the chip are clean from the residue they put on computer and make sure his conection to the throtle body is not leaking any air, I had a loose connection there and my car acting similar. I wish you the best.
Greg

What kind of plus and what are they gapped at? What other mods on the car?
Maybe it's a combination of problems.

I had a problem with similar symptoms on two occasions.

First time it was because a flake of paint came off the inside of a supercharger pipe, and it got caught on the wire on the mass air meter... made it run like trash, or not at all.

And the second time, one of the wires to the spout connecter broke, and my car was no longer increasing timing under throttle. Id throw a timing light on it and rev it up and make sure it increases.

Hope you find it, and its nothing serious.
- Jon