2000 Dodge Cummins APPS?

Yep. If your dealership thinks otherwise, ask them to look in a service manual, chapter 14, under 'Fuel Injection - Diesel'. The first sub-section is all about the APPS.

If Max340 sees this, he'll respond - he recently priced one out. As for location, look on the front of the engine, driver's side. you'll find a black plastic cover, round in the front. There's a couple of plastic clips/screws holding this on. Remove the cover, and there's the APPS.

Typical problems for a TC locking/unlocking while cruising are either a bad APPS/TPS, or a bad brake switch. An OBD-II scanner with real-time capability could monitor the throttle position, and let you know in short order if the APPS was the cause of the problem.

If you have a bit of electrical knowledge, and an analog multimeter, you could back-probe the APPS electrical connector, and cycle the sensor through it's range, watching the needle on the meter. Any erratic behavior while smoothly cycling the sensor would indicate a problem.

Thanks, Tom. I did hook it up to my OBD-II scanner and pressed the accelerator while in neutral (no load). The Actron scanner I have gives two readings, the first appears to be voltage of the potentiometer and the second may be % throttle. At the range I'm having trouble, ~1200 RPM, it appeared to be working ok, at least with no obvious dead spots. I was ranging through 0-maybe 5.3v while messing around. I did notice the % throttle seemed to fluctuate some in the 14-16% range if that's indeed what the reading was. I'll try hooking it up and driving it to see what it's doing under load. I can also try the analog multimeter you suggested next. It did kick out of cruise control yesterday, but only once. So I guess I'll try the cleaning the contacts on th brake switch too.

Thanks for the suggestions.

Jack

Well, my price was for one I bought a year ago, and I paid $320, which was with tax but below retail.

You might also check to see if your problem is the same one I had: Dealer tech did not properly connect wiring harness to the APPS after replacing the inj. pump.

Thanks, Max. I am wondering why I had the problem (less so than now) before the inj pump was replaced, and then it went away after replacement. Then nothing until a 150 mile trip last night. I'll definitely check the connectors first.

Jack