I have a 1997 chevy silverado at speeds around 65 to 70 the engine keeps dropping from 2100-1800 rpm

Question

the vehicle is not downshifting.it just like hesitates and then jumps back up to the 2100 rpm from 1800 ..this does it with or without the a/c on..engine does not miss or hesitates ..i am thinking it might be a sensor or a vaccum...any ideas would help thanks

Answer 1

The torque converter is locking and unlocking. There are a bunch of sensors that can cause that as well as problems with the transmission. Or you just drive right at the edge of the place where it unlocks, so it does it a lot.