83 Supra .... MK2 Possessed !!!!!

[Mk21983]

Hello .... All .... My Supra runs great until it gets up to normal operating temp. Then it misses and looses power . It never gets too hot. When it cools then it runs perfect again. Is it a possible a Bad Ground or an O2 sensor or Fuel Injector ? That makes some sense to me cause it run's rich until it warms up right ? The last time i ran the compression it was 160+ in all cylinders. Someone told me it could also be the Cold Start Valve. Any help would be greatly Appreciated . This car is also for sale $ 500.00 on craigslist fresno ca. I hate to sell her. If we can figure out the problem ... Then how could i sell such a great car. Thank You in Advance !!!