Q&A

The car is automatic transmission with about 125000 miles. Tranny fluid is at appropriate level. Is there a shift sensor that could be bad?

It could be a pressure control solenoid or shift solenoid. It could be related to the torque converter as well but it's difficult to say. It could also be that the internal clutch bands are starting to wear. Does the fluid smell burnt? Does this happen at any vehicle speed? Does it happen only in a certain range?

It happens whether accelarating from a stopped position or at any speed. I have read some other forums that have had similar problems. They all suggest a MAF sensor. Could it be that?

The MAF sensor is an expensive part so you'll want to check the voltages on the sensor leads and ground wire to be sure it's defective. During warm-up conditions, the voltage between the White wire and battery ground should be 1.2 to 1.8V at idle (1.6-2.2V at 2500 rpm). The Red wire should be approximately .5 Volts (only ignition on, engine off), and the Black (ground) wire should be "approximately 0 Volts" (engine idling during warm-up conditions). I've been told .2 millivolts (mV) on the ground wire is enough to affect the ECM reading but not enough to set a check engine light.

Does the feel like the car jerks forward and the rpm's come down when your vehicle speed increases? Does it feel like a slipping transmission? Are you saying that it revs high with no load but is down on power when driving up a hill?