My girlfriends 89 RX-7 has started to stall at various RPMs while driving. We've replaced the fuel pump, checked all the vaccum lines and wiring, corrected all of the ECU codes that had came up when connected to a diagnostic system, checked all of the sensors, PSI, and now I'm all out of ideas on what to do. I'm really, really irritated with it because it's been close to two months of screwing around with it and I am out of ideas.

BTW, the engine is some Frankenstein creation that the previous owner put together. Part of it is from Racing Beat and I'm assuming the other part is the original stock engine.