I have a 89 formula and a 350 tbi engine in it. I have problems with the map sensor. When the three wire connector is connected to the car it stalls and turns off, but when it is disconnected it runs great and idles smooth. When I put it in reverse it shuts off. If I gun it, the car will it stay on and when I put it in drive it stays on, but I have to gun it also. I have replaced the sensor with one on a working car and I still have the same problem. I bought the car from someone about two months ago and replaced just about every sensor you can think of and now I have this map sensor problem. Is this an electrical problem? Could the wires going to the map be in reverse cause of the car shutting off when plugged in? Is this a problem worth fixing or do I just have a lemon or something? Would it be easier to try and trace the problem or just put in a whole new wiring harness? The engine is a strong, low mileage engine out of a 1991 silverado and there is nothing wrong with the engine. I am a carburator guy and all this electronc stuff is new to me. Please any help and suggestions will be greatly appreciated.