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Q: It threw a code 21 , throttle position sensor bad code. i replaced it and the code went away but i still have no spark.

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six monthes ago i replaced the cranshaft sensor because it just died and would not start. finally figured out it was the security key. fixed that ran no problem. 2 weeks ago it started to run bad again. i checked for codes and got a bad camshaft sensor and throttle postion sensor are bad codes because it would not stat again. i replaced them bothe. the codes went away but still noe spark. whats next

My car has 187000 miles.
My car has an automatic transmission.

A: Hello and thank you for contacting YourMech...

Hello and thank you for contacting YourMechanic. The problems that you are encountering with your vehicle, could be caused by the harness to the Throttle Position Sensor (TPS) or the computer itself.

Check the harness to the TPS for any debris or any corrosion. Hook up a paperclip to the harness and turn on the key. Use a multimeter and check for voltage at the pins of the harness. Make sure that the ground on the sensor is grounded and has no resistance. If you find that the harness is having too much resistance, then I recommend having the main engine harness replaced. If you have replaced the harness and still have the same problems, then the computer will need to be flashed or replaced.

I recommend having a professional, like one from YourMechanic, come to your home to diagnose your car's no start condition before replacing any parts.

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