1995 SC300 with about 132K miles.
In the last 6 months I have replaced or changed:
Timing belt/Tensioner, water pump
Serpentine Belt, tensioner pulley.
Fuel Pump, Fuel Filter
Now the symptoms:
1. Start the car, from cold no problems at all, runs great, no miss, no hesitation.
2. As the temp starts to climb toward normal the problems start to increase. The engine runs rough, doesn't want to rev, has no power and develops a miss that gets worse the higher the temp gauge climbs. The car doesn't over heat, but once it gets to normal operating temp it is impossible