I have a '92 with a bad PCM, however, the PCM does work when the outside temp. is 50 deg. or lower. The PCM quit working this summer. After reading up about this problem I checked sensors, grounds, and determined the PCM was bad. I then wired in an external voltage regulator and have been driving the truck since then. Now that the weather has cooled down my PCM started working again. Any ideas why my PCM works in cold weather?