does it only do it after you have been over 45mph?
could be the torque convert lock up solenoid.

Answered by buddycraigg (expert)
2,499 answers provided

Egr valve sticking open, fuel regulator leaking, high secondary resistance(plugs/wires). Can you keep it running with some throttle, and does it run poorly at that time?

Answered by factoryjack (expert)
4,285 answers provided