Hi WallyM,

Glad to help. A hybrid of some research and some guesstimation.



You may have a faulty ground the TPs uses. Yep, I'll bet, if the factory installed TPS, it could be faulty or failing from dirt and moisture intrusion. The TPS can be failing, and sometimes the ECU has such tolerance, it won't report a faulty ECU.

Though each time the TPS (switch, the the LH-Jetronic 3.1 Throttle Position Sensor TPS) was beginning to fail, causing one of the 1989+ 240s to get the funky munkey and run poorly, with maybe an emission control or other fault flashing at the OBD LED, it was the TPS. I have several spares.

Remove the wire harness connector and tested the TPS using multimeter continuity function. It was faulty and had no continuity when the throttle was closed, yet continuity in the middle of the movement range. It was bogging when trying to accelerate on the 1991. In another instance, it would not idle on the 1990. Yet no OBD fault indicating TPS if any OBD fault code at all.

You can get dirt and also the copper contacts inside wear and can break. The TPS is not too well sealed.

Welp, you are closer to resolution. I guess you have no garage like me.

Happy Wednesday!

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