carb to tbi

I purchased a 1987 nissan sentra hatchback with a 1.6 engine back in march. Shortly after i drove it for awhile it started runnign rough and dumping a lot of fuel in the throttle body. I took it to a mechanic and have come to find out that originally it was a carburated engine and someone had changed the intake over to a TBI. A lot of the sensors were supposedly missing or not working properly. The ECM was changed over as well as the wiring (I suppose). This thing is giving me fits and I've changed to Idle control sensor that a nissan dealership had said the computer was shooting a code for. I changed it and it did'nt make it any better (probably because of the change over). The latest mechanic who told me the engine had been changed over said that possibly the temp control sensor on the throttle body could be the culprit. The o2 sensor has also been changed. I see a lot of info about the fuel regulators as being suspect too. The car is really in good shape and starts up everytime and is really a strong runner. It is just the fuel problem that is freaking me out. Any hints?:banghead: [email protected]

swap to a newer ga16de? might be cheaper