new to the forum and could use some diagnostic advice.
1986 E150 w/351 4bl/carb auto trans.
Runs rough unless you apply gas at high RPM. Once moving the transmission will
not shift gears. So far completed the following:
Converted air conditioning, replaced water pump, carb, tune-up.
After this work was completed the engine ran great for about 1000 miles. Now it is back to the rough running and not shifting.
Thanks for the advice in advance

 

Which transmission do you have? Perhaps the modulator line if it has one is off.

 

Transmission is a C6. Line look fine. Modulator replaced 6000 miles ago.

 

Pull the vacuum line off the modulator. If thans fluid is dripping you found your problem replace the modulator.

 

tranny may need serviceing or adjusting. as for the motor check plug wires, timing and fuel filter