this is kind of a long shot... but go and pick up a set of Motorcraft OEM plugs Model number AYFS22FM
STOCK NUMBER 4112 at autozone.
I had Autolite DP's. and they gave me a REALLY hard time at lower RPM's and when I Really horsed the engine. I got my Motorcraft plugs, I now hardly ever have a problem. I got 1 misfire on my way down to the meet Saturday, and one on the way back. Only reason why I got them was because my Fuel system needs to be cleaned out. my injectors are a little dirty.
