97 Mountaineer stuck in Closed Loop???

I have transplanted a 5.0L from a 97 Mercury Mountaineer into a 89 Bronco II. We are having trouble getting the engine and computer to come out of Closed Loop. The engine will run fine until it reaches 195 degrees(at which point it should change to open loop), but above that temperature it runs really rough and lopes severely. Does anyone know what might be causing this, or how we can get the computer to convert the the open loop? Any info would be appreciated ASAP! Thanks!

I have transplanted a 5.0L from a 97 Mercury Mountaineer into a 89 Bronco II. We are having trouble getting the engine and computer to come out of Closed Loop. The engine will run fine until it reaches 195 degrees(at which point it should change to open loop), but above that temperature it runs really rough and lopes severely. Does anyone know what might be causing this, or how we can get the computer to convert the the open loop? Any info would be appreciated ASAP! Thanks!

I saw some info on the explorer post that said it can be caused by a faulty temp sensor or thermostat. Try those and post if it takes care of the problem