I have a 2000 Z71 with a 4.8L engine. When I drive it for approximately 30 minutes, stop, then take off again from a dead stop, It shifts extremely hard from 1st to 2nd. I have recently had the transmission rebuilt, as well as replaced the torque converter, but I still have the same problem. I was instructed to replace the Throttle Positioning Sensor, which I have a hard time understanding that suggestion. Anyhow, I replaced the TPS, and the problem still exists. If I shut the engine off for 30 seconds the problem goes away. I can drive another 30 minutes and the problem returns. It only happens after a somewhat lengthy drive. Could my governor be defective, or is it something else?
Thank you.