First, I apologize as this isn't technically a ram (05 dakota). But the issue is with the 4.7 motor in general (vehicle shouldn't matter much) and this forum has a different (new/larger) audience. Which I need because I'm at my wits end here.

I'll attach a video to help.
Essentially, when I test my TPS sensor on the vehicle (probing the middle wire essentially), at idle I'm only getting 0.17volts and at full throttle about 0.80 volts. The service manual says spec is 0.5volts at idle and 3.5+ volts at full throttle. I have tried 5 different TPS sensors with the exact same result. The original sensor (brand unknown), an Ebay sensor, 2 separate new Duralast sensors (Autozone), and a new NGK/NTK sensor. All five have the exact same result when installed on the vehicle. The only way to get 0.5 volts out of any of them is to insert the TPS in the slot of the throttle body and rotate the sensor dial about 70degrees past where the bolts line up. That all said, I'm getting a P0068 code with a very rough idle and an occasional stall in park and the MAP sensor tests good. Also note that I get similar results off the vehicle when I hook the TPS up to 5v on the bench and rotate the sensor with a flat head screwdriver. All 5 don't reach 0.5v until about 80-90degress from the start position. Which cannot be done when installed on the throttle body.

What is going on here? I see videos of people testing the TPS sensor and it's definitely at .5v at idle position.

 

See what the input voltage to the sensor is. Should be 5 volts.

 

It is. I get a solid 5v and good ground too.

 

Think I would address the TPS problem before worrying about the other code. I suspect it will go away once the TPS is resolved.

Input voltage is correct.... Is that testing with the sensor installed, and plugged in? If so, then you seem to have extremely bad luck with sensors. Pull the sensor, and test resistance at what should be idle. Go to the parts store, and test a few more.... if they are all the same, regardless of manufacturer..... (I think I might also check sensors for different years as well.) there has got to be something else going on.

You are installing it properly? Right? (I have to ask.....)

 

Yeah, I'm checking the "sensor wire" voltage with the TPS connected, 5v and ground wires, to the vehicle plug itself (through use of alligator leads). With the key in the ignition.

You know, you'd think that has to be what's wrong. LOL. 5 separate sensors reading the exact same kind of wrong is bonkers. But I don't know how I could be installing it wrong. I've rebuilt engines before, and installing this TPS isn't that complicated. The throttle body itself looks right too (researching videos on youtube of "how to install a TPS sensor"). That's why I'm over hear in tears with frustration. Staring at this damn truck for an hour rolling over in my mind what kind of simple thing I'm just missing. Can't think of anything.

What I need is a known good one. Maybe I'll bite the bullet and buy a used throttle body on Ebay with all the sensors attached. Those are mostly pulled from running motors out of wrecked trucks.

 

P0068 MAP Sensor/TP Sensor Correlation Vacuum Leak Detected
This code is not saying the tps is bad.
https://obdcodelookup.com/dtc/p0068/

 

In the service manual under the P0068 troubleshooting pages, it does indicate that a vacuum leak is the most common cause of this code. However, the code is essentially saying that the readings between the map and the tps aren't lining up. Which does sound like my issue.

And in the troubleshooting checklist for the code it has you check the tps for proper operation, and mine constantly fail that test. I'm just in awe that five different sensors (most new and name brands) all fail it the same exact way. My lizard brain can't accept that I got five sensors that are identically bad.

 

I agree. The odds of that are way out in left field......

Wonder if something in the throttle body itself is screwed up??? Any junkyards near you? Maybe grab a used one, complete with sensor, and see what happens?

 

Yeah, that's what I'm thinking. Or eBay. You can usually find a listing from a rear-end Collision truck that's totalled. They go for about 40 bucks with sensors.

 

That sounds like a good plan.