The truck waivers in speed up and down about one tach point whlie driving any speed, 20 to 70mph. You can see the tachometer move and you can feel it. The truck has done this for years. Six different shops have looked at it and none could figure it out. The truck idles smoothly. The truck accelerates smoothly. It does not bog down, misfire, stall or make any unusual noises. The truck "gets better" if the brain is flashed but soon gets "sick" again. Additionally, recently the truck (auto tran) goes in and out of gear frequently as if it can not make up its mind, this is new and is about 500rpm change as opposed to a one point change. This bigger change began right after a trans fluid change this month. Any help is appreciated. I'm sure you have heard this before, but I have little money to part with, I have paid so many so much for nothing, if you tell me what to do and it fixes it I will send you no less than $100. I would pay anyone who could give me the answer to this problem! This has gone on for years and no one seems to be able to figure it out. I think it is a sensor or a short and the brain gets "derailed" worse and worse.
Oct 20, 2009 at 8:41 PM