2001 GPGT naturally aspirated, 96000 miles:new gas filter, fuel pressure ok, new transmission fluid and filter, checked EGR clean and functions properly, replaced with new gasket, replaced plugs, new wires, swapped coils and wires to see if problem would move to another cylinder...stays #5, removed injector rack and injectors...cleaned and replaced using new o-rings...same #5 misfire....changed position of injectors to see if problem would move...no luck same #5 misfire, changed PVC, sprayed carb cleaner at all possible points for vacuum leak, checked compression twice to be sure...no significant difference between cylinders...155-160psi, new air cleaner, checked signal to injector..all good, engine idles perfectly, engine accelerates under partial pedal with no issues, under full pedal engine accelerated up to 4500rpm and then begins to "skip" and hold at 4500rpm until I back off on throttle...car easily does 85+ but I need to ease it up to high speed because under full throttle the engine does not accelerate past 4500rpm. I am now considering dropping the exhaust pipe (soaking with penetrating liquid) to see if back pressure may be the issue? Any suggestions? Is it possible that the rpm limiter is faulty?
