Unfortunately no one here would be able to help you... The only sensor that really fails on the car that would cause rough downshifts would be the VSS. The VSS is a twofold sensor (mechanical for the gauge panel and an electrical hall sensor for the PCM). The electrical portion is the part that fails. Off hand I beleive it will toss a cose 452 for an absent VSS signal however it's possible that you may have an innacurate signal which wouldn't trip the code.
Look on our page (
www.midwestsho.com) on the lower left for info to run the codes.
Symptoms of a failing VSS:
- Variable assist power steering gets firm then soft during sweeping turns (onramps, etc)
- Rough or no downshifts
- Extremely hard downshift when bringing the car to a stop just before coming to a stop (this is the torque converter manually unlocking)
- Cruise control inop