I put a 964 engine in a 914 Porsche a few years ago. It has always run great until recently. It starts and idles fine but during acceleration (as the accelerator pedal is depressed) it just goes flat. It misfires as if the fuel delivery has been shutoff. If I depress the clutch while holding the throttle open the engine just continues to misfire (rpm does not increase). If I back out of the throttle it will run fine again. Fuel pressure appears to be OK and I have tested the MAF sensor per several videos on YouTube and can not find the problem. Anyone have any ideas / suggestions?