Hey my acceleration is stuttering it sounds like it is misfiring, it does it at about 4000 RPMS-8000 no matter what and under 4000 it will do it occasionaly, and the idle doesnt seem to be doing as well. I changed the spark plugs and the timing seems good. It was running fine till the other night when i got back and was adjusting a ground wire it's one that goes into the main fuse box. I also messed a little with a MAP sensor but nothing big. what can cause this stutter and slow in the accelleration to happen?