Q: Replaced TPS but now car doesn't decelerate unless I press the brake and slow it down that way.

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I didn't have any problem slowing down before even with the bad TPS. Mechanic thinks it is a faulty TPS because it is not responding during a certain point in the reprograming.

My car has 125000 miles.
My car has an automatic transmission.

Hi there. Sounds like the cruise control switch is malfunctioning and keeping the computer engaged with the throttle position sensor (TPS). Check the cruise control switch and see if it sets, increases speed, decreases speed, and disables. When disabling the switch with the throttle off, the vehicle should begin to slow down. If the cruise switch is working correctly and the vehicle is not slowing down, then the problem is within the throttle accelerator pedal position sensor (TAPPS). If you need further assistance with your vehicle not slowing down on its own, then seek out a professional, such as one from Your Mechanic, to help you.

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