I have studied all the threads on this TPS and 3-4 shifts in and out of O.D. Now what I need someone to explain to me is why on a 140 mile round trip to work everyday this thing only acts up about once a day or sometimes not at all. Seems to me if the TPS windings were bad everytime the wiper passed that spot you would have a voltage spike and trip the 4-3 shift, Likewise if the wiper is bad seems the voltage would be off all the time. I have adjusted TPS and found it to be in spec.<br> So is the TPS to blame with an intermmitent shifting in and out of O.D. What say you?<br><br> JJ<br><br>92 4x4 cab. 75,000 miles.

 

Calvic, i've also heard that the tranny temp sensor plays into this too. If you want one better than that, I installed the Isspro tach to operate off of the factory crank sensor, tach wouldn't work, so I bought the magnet kit, had to raise the factory crank sensor to clear the magnets, the A/C quit working and it wouldn't shift to 4th unless I took my foot off the pedal, adjusted the factory sensor to .020 from magnets, A/C works and it shifts out at 52-54 mph, and TPS was already set to correct voltage. Don't ask me why, but it works now??????????????????????

 

The crank sensor bites alot of guys in the behind as it isn't critical to operation of the truck but does tell the PCM that the engine is running.. It engages the A/C, OD and also you would have noticed no charge from your alternator.<br><br>As for the intermittant shifting, the temp sensor, TPS or both could be bad. If the windings in the TPS are bad, temperature could also make it flub up once and a while. Since you have worked on the TPS maybe try the tranny temp sensor. ???<br><br>J-eh

 

I'd check:<br><br>TPS<br>Crank position sensor + wire/connectors/leads<br>Speed sensor/wires/connectors/leads<br>Throttle valve cable setting (kick down cable although not common.)<br><br>Does your truck have cruise control??<br>If so check for vacuum leaks as this will trigger down/up shifting.<br><br>Bob.<br>