I have a 2000 model Ford Escort ZX2 with a 2.0l DOHC engine and a manual transmission. Not sure how to tell whether it is Z-Tec or SPI. Anyway, the problem I am having is that the No. 2 fuel injector is dumping a lot of fuel into the No. 2 cylinder; it shoots out like a geyser when the plug is pulled. So I switched the No. 2 and No. 3 fuel injectors to see if it was a bad injector, but it still did the same thing. Now I think it is the pulse going to the fuel injector from the PCM (ECU or ECM) that is causing the problem. I have found a PCM from a salvage yard, but the part number is XS4F-12A650-BD and the original from the car is YS4F-12A650-ZA. It is for the same car, same engine with federal emmissions and I do not know why this wouldn't work. I have tried to get help from ford dealership service techs, but they don't seem to want to help me. I have also tried to call ford headquarters and speak with the engineers that designed the PCM's, but they won't let me. Does anyone know how ford breaks down the part numbers for the PCM's and whether you can interchange them or not? Is there a way to check the PCM on a laptop? Also could this problem be caused by something else (others have said maybe a short in the injector wiring)?

Thanks,
Jackie