Hi new guy here looking for advice. Have a 1997 7.3 psd with Banks kit- Just bought it from my father-in-law. He was original owner. Has 119k miles, it has sat on and off for a few years. Changed oil, trans fluid, coolant. Just drove it 1k miles to Florida. Drove it around here for a week no problems til now. Now if I start it in park it starts rough, lopes, black smoke. if I start it in neutral it starts great no smoke. It seems to be using more fuel and shifting harder. It's 90 degrees here-not cold.
I saw a previous thread that this could be TRS sensor?
Took it to Ford dealer, big shop does diesel only. tech said he never saw this neutral/park situation before.
He thinks it is under valve cover wiring ? He said it ran fine with no codes.
I don't want them guessing/throwing parts at it.
Any ideas? Thanks!!

 

MPLS (neutral safety switch) is bad

 

Will that just effect starting or fuel consumption and shifting ? Thanks !!

 

So will this just effect starting ?? Or ? ? Does that effect shifting while driving also ?? Thanks !!

 

If it's out of adjustment, it could affect a lot of things, including shifting, starting and the reverse lights. If it's just a matter of it not sending the right resistance in the PARK position, you're probably okay. Thing to do is measure the resistances and continuity of the pertinent terminals on the switch with the gear selector in each position. The EVTM has the specs of what terminals should show open / closed and what terminals should show what resistance in each position.

 

Took it to the dealer. Told them nuetral switch. They didn't believe me. Wanted to check wire harness under valve covers. Showed them started perfectly in neutral. Rough In park. Tech said he'd never seen that before. They replaced neutral switch and trbl is gone. Thanks !!

 

Good to hear.

Now you know not to go back to that dealer