I just change the spark plugs on my 1990 and i gapped them at .054 now when im in first and in second if i slam the pedal to the medal once i get up to like 3.5 rpm its bogs down mo power. i can not redline it in first and second it just drops rpm once i get that high. maybe even third have not got it there yet.any suggestions.

 

HELP ME PLEASE
NEW MUSTANG OWNER

 

It didn't do this before changing the plugs?

Stock motorcrafts are cheap enough, I'd get another 8 plugs and go through it again. Doing the plug wires & cap/rotor while I was at it.