tps sensor Question?????????

I clean my throttler body with carb cleaner and I dont know if I mess up my tps sensor. The problem that I have now is my transmission is downshift hard around 20-25 mph sometime not always when the engine is cold everything work fine no hard downshift no steering vibration it run like new once the engine start to warm up you ca feel the a strong steering vibration at idle and transmission hard downshift but if I stop hard on the brake I don't feel no hard downshift is weird any advised? I was thinking that I have a worn out or weak tps sensor giving fault information to the PCM

1999 Ford Explorer 4.0 OHV with 145k,miles

4 Answers

  • Grizz
    Lv 4
    9 years ago
    Favorite Answer


    It sounds as though the PCM thinks your foot is hard down, which could be due to a problem with the TPS. If it is a 3 pin TPS then you can check it with a volt meter.

    One pin will be earthed, one will read around 0 volts, & the other will read around just under 5 volts or thereabouts. As you open the throttle, the 0 volts should increase smoothly & the 5 volts should decrease smoothly, both of them in relation to the throttle opening.

    Very best regards


    Source(s): Mobile mechanic
  • 9 years ago

    In order to properly diagnose your problem completely, The vehicle will need to have a pcm scanner put on . The transmission is controlled by the pcm for the shift points. The pcm uses a number of inputs in order to determine those shift points. TPS, Maf, Map, CKP just to name a few. Each sensor input needs to be checked for proper operation. The vibration you feel could be a spark plug that is missfiring untill it gets warm. Have a qualified technician check the sensors and plugs. Also there is no vaccum line that goes to your transmission for a modulator. Your transmission is completely controlld by the pcm.

    Source(s): I am an AutoTechnician of over 20 yrs exp.
  • 9 years ago

    Remove and clean your IDLE AIR CONTROL VALVE. It is held in place with 2-8mm headed screws. It controls power, emissions, and fuel air mixture. It gets FULL of sludgy vapors and stops fine tuning engine mixture. CLEAN it out, and your throttle body AGAIN!!! Everything will be FINE!!

  • Anonymous
    9 years ago

    you have a vacuum leak some where check all vacuum hoeses . an one from back of manifold to transmission to modulator

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