my friend has a 94 z28 a4. mods are pacesetter longtubes, ory, cutout and flowmaster. stock intake w/ k&n filter, msd coil, new plugs gapped @ .045, new wires, !EGR & AIR., street tune by herron performance

this car started having a bad low rpm warm engine only misfire after we installed headers and everything else listed above minus the tune. it threw a MAP sensor code and that was replaced. car has been triple checked for vacuum leaks and injector problems. fuel psi is good. the car runs fabulous (no misfire) above 3000 rpms and at WOT. it actually pulls a tad harder than my 95 with same mods.

when the headers were installed the egr was removed to get the holes welded up by a local shop. they were leak checked before installing. the car was ran for maybe 5-7 miles with the egr holes uncovered to get to exhaust shop.

scanner shows about 42-45* of timing at ~2000rpm cruising. WOT timing is around 38*, it smells very rich at part throttle drivng as well.

we have no idea wtf is goin on with this thing and it is getting very aggrevating and expensive for him.

 

does no one have any insight???

 

When in DOUBT blame the OPTI!!!

 

we have thought this. but would it not cause it to run bad up top if it was the opti? could the ignition module be bad on the low rpm side?