Hello and thank you for trusting Just Answer with your question. I'm Dj.
There are a lot of things that could be causing this, so it's a process of elimination.
Does the truck seem to have a normal amount of power?
Is it running smoothly?
Does it shift into overdrive at about 40-46 with light throttle?
Does it feel like there is something pulling the truck back?
Do you have a volt meter?
Have you checked the timing with the jumper in place?
If you can give me some more information, we can start to narrow this down.
When the truck is idleing it runs perfect, however when you need a little extra power from a start or rolling about 5 miles per hour or so their is a loss of power.
It does feel like something is holding it back.
I have a volt meter
The truck does shit into overdrive around 50 with throttle.
I havent checked the timing. was wondering if the vacum reg. isnt working properly becaus when the AC is on the idle is high.
There is a solenoid that bumps the idle up when the AC is on.
So that's not the problem.
When you checked the timing, did you have a jumper between TE1 and E1? You have to do this to set the timing accurately. I just use a regular sized paper clip bent into a U shape.
It sounds like the timing might be retarded. This can cause all of your problems except the shifting.
The engine coolant temperature sensor sends a signal to the ECU telling it what the engine temperature is. If it's wrong and telling the ECU that the engine is cold when it's not, the ECU will make the engine run rich and it will also not allow the transmission to shift into overdrive.
So if it shifts into overdrive within about 5 minutes of starting driving, it's OK. If it takes longer than that, the sensor is wrong.
If the truck can't shift into overdrive until 50 MPH, the cable that goes from the transmission to the throttle body is adjusted too tight. Loosen it one turn and see how it works.