ok...replaced the o2, tpc and map sensors, the truck now runs like a dream, but it doesn't seem to want to downshift into 1st when i come to a stop. I have to manually shift it down...any ideas?

 

Sometimes your coolant temperature sensor is associated with the lock-up converter maybe that could be stuck or maybe the lock-up solenoid in your transmission is n't working properly

 

Possibly could be a speed sensor about to go out, i realise you're having to replace a whole bunch of crap but trust me it's worth it in the long run because by the time you fix the problem you basicly have a perfectly good running truck.

Now go replace the speed sensors, there is one ontop of the driverside of the transmission, and also one ontop of the rear pumpkin depending on what year's yours is.

That controls the speedometer, and some shifting also.

Try that then work your way up to the transmission it self, could possibly be something to do with the valve body also but i wouldnt consider messing with that your self and that would also be a last resort once you've exhausted all other ideas.

 

took it out for a drive this am, was having the shifting problem for a bit then it just went away...everythings running good now. One person told me that a piece of crap may have gotton stuck in the lock up solenoid. Hopefully that is the cause. Guess i'll start socking up some cash in the event of a complete trans failure, but for now all is good...next stop...dual exhaust