I finished my car awhile ago. I have had to have it pro tuned on the dyno and at the time he put in new plugs. Well that was about 2500 miles ago and I have had an issue. I changed from an auto trans to a standard. I had someone here burn a chip for me but it wasn't worth a **** so I went back to the orig. one I had burnt. Well the plugs are black and carboned up.

Could I just need to go out and drive the damn thing hard or change the plug heat range? It seems to run fine. It does load up alittle at cruising speed but that was with the chip this guy burnt for me cause the tranny change.

The engine calles for AC Delco R43LTS, the shop put in NGK R TR55 V-Power

It is a crate motor and I have all MSD ign. Headers, GM Performance intake, Vortec heads, and I have a VAFPR set at arround 26#'s.