Wierd Misfire/backfire question....
 

I have a 1990 FM2 kit and when i put it past 9-10 psi at WOT the whole car studders and makes a light poping noise. Its almost would feel ike if the car stalls for a split second. If i give it half throttle it doesent do it no matter what psi im at. The higher the RPM the worse/easier it is for it to happen. This happened like 4-5 months ago and i changed my spark plus wires and it went away, now its back. Any ideas?

coils fueling what does your wideband say? Have you been over your grounds?

AFM brushes

It should be an OVER FUELING problem... just the matter of finding what's leading to your over fueling!! O2 Sensor? AFM brushes comment by Olderguy? Overlapping FMU ( like myself) haha!

That happened to me when I was running out of fuel before (my pump died).... what kind of fuel setup do you have? Does it happen running full throttle at 8psi for example?

When the FP died in my car, on the way home from the track, the car would feel like it was going to stall. Kept it out of boost... but all of a sudden, no power. AFR gauge would go "black"....

Swapped out the FP for a 255 walbro... and it was all good. No poping or anything....

Popping sounds like silly rich.....

Dave,

FM2....datalog the Link and send it to us or FM.