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I tried and did notice a change in the ohms, however it was inconclusive in my mind because I couldn't be sure if it was my hands moving the test lead on the contact point or the wire doing it the way I was contorted to reach everything. I'd need someone else for a 3rd or 4th hand to be sure. A better scan tool would help as mine doesn't see everything live. I do know adding the ground did make the throttle % drop about 2% consistently when I would add and remove it. So I'm sure there was a ground issue, whether or not it was definitely s165 or not I cannot say.

When I tested my grounds they all came back fine with the tester not showing ohms, just going back to the blank screen with the - that it was making contact. I tried very hard to get the truck to act up in the shop and it wouldn't do it, reving, on jack stands in gear, even holding the brakes to get it to sort of "load" the engine. Nothing made it act up until I got it on the road and you could tell it wasn't fixed before it left first gear. Now here is my theory, right or wrong. S165 is somewhere in the ball of wires right out of the ecm, that spot lays on the engine mount. In my case I think the engine rocking when under load is just enough to mess with that bad connection and make it rare it's head. It would also help explain why when it would take fits and run it's worst my oil pressure would act up and I got the map code, and when hauling a load it seemed worse, but I thought that was my imagination. Mike, thanks for your wiring diagram, I used that one and the other two that go with it and it was a HUGE help. Even though I just joined, I've used a lot of the things you've posted on here and other forums over the years and figured things out with them. This was just the first time I needed to ask something.

I could not find any grounds on the ecm, all the blk/ltblue wires went into the loom but I couldn't find where they all went together without unhooking the harness from the ecm and unbolting it from the block. I tapped the blk/ltblu wire going to the apps and took a test drive and NO MORE PROBLEMS! No more tc/od issues, map codes or oil pressure dropping. I came back and soldered it and taped it up, drove it about 50 miles with no problems at all. I realize it wasn't a perfect fix as I still have a bad connection at that junction but the truck is at least drivable now. If the problem arises again at least I'll have an idea where to go. One other thing, the black/tan ground that goes from the passenger battery that everyone foils/moves, where does it go? I read it is supposed to be an ecm ground but never found the other end of it in the loom, I could have missed it though is it's not easy to see down there. Thanks again for all the help from everyone!

Okay so more testing, I found another dvm and it is reading between .012- .018 AC so that seems acceptable. After some more searching I found a wiring diagram posted by Mopar1973man showing the apps, map and oil pressure, plus some others all going to an s165 ground junction. I've looked and can't seem to find it, from what I've found its most likely in the loom by the ecm. I pulled some of the convering off but still don't see it, so I'm going to add a new ground to the blk/ltblu wire and see what that does.

I'd agree that sensors fail, however how fast all the problems arose is what has me scratching my head thinking that they may be related. This has only been going on for about 100 miles, and 30 of that has been troubleshooting test miles. I read your article on the map sensor testing but my scan tool won't read the map sensor data on my truck so I can't do much testing until I find someone with a better scan tool. As for the trans speed sensor, I haven't messed with it, no codes other than the map sensor one. My problem seems to be consistent with what I'm reading with people having a bad ground or alternator, apps etc... The scanner showing the throttle jumping all over while cruising and not moving my foot, tells me something is interfering with the apps signal or ecm, which would cause the erratic tc/od issues. Am I correct in thinking by removing the alternator fuse and regulator wires from the back it should rule out that as the problem? Also I have a tc lockup switch and when it acts up if I lock it the tc stays locked but throttle is still all over the place. That doesn't really help much but I figured I'd throw that out there.

No, only oil pressure, and on the last test drive I got a p0237 code, not sure a map problem would cause a torque converter /od issue so I'm leaning towards that is just because of my other problems.

I reread this thread to see if I missed anything and apparently I missed others having the 30v problem with cheap multimeters, sorry about that. I checked all the grounds again and and reset the apps for the 3rd time while I had everything disconnected. No change, so I removed the alternator fuse and the voltage regulator wires from the back of it and still no change. Idling and light load it's fine, anything above 20% throttle and it gets worse. If you watch the throttle on the scan tool it's all over the place when it's surging. Eliminating the alternator from the circuit "should" rule it out I would think? It also started today with my oil pressure dropping suddenly when it's doing it's surging the worst, idling or light throttle oil pressure gauge is fine. It leads me more to think it's a ground issue, but all the terminals are sanded and tight.

Yes the lowest setting it has its 200v. I was hoping it would give me a ballpark idea since it has a decimal and another zero but it doesn't look that way. I may have to pick up a better one to check further. Any idea on the humming coming from the alternator with the key on? It never did that before, it goes away if you unhook the voltage regulator wires from the back of it.

I have been fighting an apps issue, it started with a TC lock /unlock issue and has escalated to a throttle surging issue. I checked the grounds and was getting erratic readings on my scan tool from the apps with the key on and engine off. I figured the apps was bad so I replaced it with no effect. I've read through this thread and tried testing my ac voltage and am getting 30 volts! The alternator is also humming/buzzing with the key on ,engine off. I'm pretty sure my alternator is at fault but what's throwing me is unhooking the alternator fuse doesn't change anything. Truck is an 01 3500 auto 4x4 with a quad adrenalin.