Q: Truck idling high and shifting at high RPM when let off throttle

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Yesterday morning when I cranked my truck I noticed it idling higher than normal in the driveway. It was also rocking back and forth between ~850-1250 RPM. It usually idles at just under 1000 consistently. Upon leaving I backed out and switched to Drive, everything seemed fine until I start moving forward. This is when the RPM just started to climb. At about 3500 in first gear I let off of the throttle and it shifted. Same for 2nd, 3rd, so on...Until I got to high gear, no matter how much I pushed the throttle the motor wouldn't rev beyond around 3000 with no power. This morning it has the same symptoms. I checked the transmission fluid and it is fine. I have never had any issues with the transmission in this truck and have owned if from brand new. Please help.

My car has 220000 miles.
My car has an automatic transmission.

Hi There, What you are describing sounds like possibly a bad speed sensor or potentially a faulty transmission control module, which also controls the speed sensors. The transmission control module has various sensors such as vehicle speed sensors, wheel speed sensors, throttle position sensors, turbine speed sensor, and transmission fluid temperature sensors that all direct information to it in order for it to perform it’s function. Other functions controlled by the TCM are components such as a kick down switch, traction control system, and cruise control module. Any of these may also affect the way the transmission control module performs and controls the transmission and the shifting of your vehicle. A faulty transmission control module may cause also cause a delay in acceleration or erratic shifting of gears. Lastly, this may also be a result of low transmission fluid. I would suggest having a professional from Your Mechanic come to your location to properly diagnose your transmission problem.

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