So after my 1996 Mustang PI swap made 254 RWPH I was not satisfied. I found another mechanic that says that I have an exhaust leak and that the tune in the car is crap. I explained to him that once and a while the car has a horrible Idle. It has like a vacuum leak but I have checked several times and nothing. When I am on the Highway going 80 my RPMs are at 3,000 and I have 3:73 gears and I have adjusted my speedometer. Then when I park the car the the car will idle at 2,000 RPMs. This happens once and awhile several times when I drive my car. The mechanic took out my car for a drive with my tuner plugged in and said it has to much timing. What does that mean? Should I have it re- tuned? It has stage 1 comp cams and Mac long tube headers.