i have an e4od in a 91 f250 diesel 4x4 at some times it randomly shifts into nuetral istead of next higher gear when accelarating or stays in lower gear and wont hardly shift out also the overdrive light always blinks but overdrive works trans is ford recon with 20k ford replaced wiring harness but did not help i adjusted the position sensor but did not help please help
Codes, fluid colour/condition/odour/level may help.
What you are describing is typical of a bad MLPS or nuetral switch as some call it. I think you called it a position sensor. Adjusting it won't help. Replacements are readily availably in the aftermarket for $30-$40. It should come with an updated connector that is designed to better keep moisture out which usually causes the earlier type to fail. Just follow the instructions in the package. Use a good dielectric grease to protect the contacts from future moisture. Vaseline will work if nothing else is available to protect it from moisture corrosion. You may also want to check your TPS very carefully. This is best done with an analog VOM (with a needle). Disconnect the sensor from the harness and move the throttle very slowly through it's entire range. Watch for any sign of anything other than perfectly smooth change up to about 3/4 throttle that would indicate a bad spot. This is a mechanical sensor and is subject to wear just like the MLPS. Neither of these sensors will always set a fault code unless they are just plain dead.
Lugnut
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