Still breaking up after 6000 rpm.there are a few plugs that have oil on them.i know I need to do valve cover gaskets and plug well seals,but just to check if it helped,i Changed plugs and wires.all from sho source. I don't daily this car if I don't have to(I have a mustang gt also),so don't bash me on changing plugs and wires first.it Made a big difference,but didn't totally fix it. Could the accel coil be a problem?? It was on car when I bought car over a year ago,and the car sat for two years before I bought it. I've heard the accel coil is junk.