The engines behavior is very irregular. Usually when I first start the car it will accelerate normally, until it reaches past 2500 to 3000 RPM. then it starts to stumble and loose power.
Spark plugs, Ignition wires, Coil are all good. I have not found any vacuum leaks, and the throttle body base gasket( between throttle body and intake manifold) is brand new. Air filter is fine. Full pump, and fuel filter has recently been replaced. Original Fuel injector has been swapped out for a used but lower mileage unit. adjusting ignition timing does not seem to help either.
I also noticed that on acceleration, the engine will rev up, but the transmission won't shift up until I let off the gas a little.
Spark plugs, Ignition wires, Coil are all good. I have not found any vacuum leaks, and the throttle body base gasket( between throttle body and intake manifold) is brand new. Air filter is fine. Full pump, and fuel filter has recently been replaced. Original Fuel injector has been swapped out for a used but lower mileage unit. adjusting ignition timing does not seem to help either.
I also noticed that on acceleration, the engine will rev up, but the transmission won't shift up until I let off the gas a little.