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@tayto mentioned ignition switch, I'd look into that as a possibility as well...Just note that if you end up replacing the ignition switch yourself there's a VATS reset procedure you'll have to follow if your truck is equipped with GM's vehicle anti-theft system (not sure what the first year was for that system). Otherwise, truck will never fire up.
Have you conducted a pressure test combined with a live data feed test drive to confirm it's a pressure-driven issue or just going by what you see in that screenshot?
No, but I have read several post on forums like that. With the 4160e, and the ones who have figured out what the issue was all said that the pressure increasing, is due to something internally failing in the transmission causing the pressure to build up at highway speeds and then when you slow down to a stop. The the harsh shifting happens. And will continue until you turn it off. And let the pressure go down. That's been my exact experience. Like you we're mentioning the tps sensor could be at fault. And I had a tps sensor code. I've heard that a bad solenoid valve was the cause of some others. But also that a bad pcm, ect was the culprit. What I can say, since wensday. Anytime I drive at highway speeds for more than 15 minutes or so. And slow down to a stop. The service engine light pops up and then it's shifts extremely harsh 1-2 and a little on 3 to 4th is perfectly fine. Stops after turning off for a few minutes. Tbh we don't have alot good transmission guys around here. I would have to drive an hour away to find someone. So I have been after trying to figure it out if someone else has had similar issues or not. And what caused it. To get a general idea of what it could be.
Yeah your right man, you enjoy your weekend too.
Connect a scan tool, look for "codes" but also examine the data stream. Find out what the computer wants you to know. This seems to be a "limp-home" issue. The computer is programmed to increase line pressure when certain sensor signals go out-of-range.
