89 Supra problem

[rs2800]

Howdy folks,

I recently inherited an 89 Supra 7MGE non-turbo automatic from my nephew. He was having problems with it and wanted to get rid of it. So I traded with him and put a JDM engine in it and painted it and it looks really good. The car has only 116k original miles on it. Now for the problem. It runs great most of the time. Does not over heat, have oily coolant or water in the oil. All fluids are great. Occasionally it will sputter and idle rough and die and when you start it back up or rev the engine white smoke boils from the exhaust for a few seconds and then it will run fine again. It has only happened a few times but is starting to happen more frequently now. The check engine light is on but it only throws a code 22 which is the temperature coolant sensor. I have replaced the sensor but the light still comes on frequently. Anyone else out there experienced anything like this. I'm kind of scratching my head at this point and don't really know where or what to look for next. Any help, advice or suggestions will be appreciated.

Thanks