So I have had some engine issues for a few weeks now... The car runs fine under full throttle, however pretty much any less than that usually around 2500-3800 RPM the car will start to hesitate. Then from there if you back off the gas some and get back into it the engine runs good for a while... If you dont back off the gas it starts hesitating worse and sounds like it shuts down a cylinder or two and runs/sounds bad! Then if you turn the car off while you are still going then re start it, the car goes back to normal... and this is a repeating cycle that doesnt end!
I have replaced:
Idle control valve
Yet the car still is doing this.. I am thinking it is either the ECU or a VANOS problem
By the way it is an 03 ZHP with 115k miles and intake headers/full exhaust and AA software...
Any input is appreciated!