This is an issue that has plenty of discussion for sure. I'm hoping someone smarter has HAD the same issue and is able to list two or three likely reasons for my issues. I want to pardon my descritions upfront if I don't exactly use the correct terms to describe my situation.

1. The truck starts and runs but the idle is not quite right and the engine will stall if placed in D or R.
2. The engine and trans has been rebuilt and all sensors have been replaced with new Mortorcraft parts in an effort to circumvent the very issue I am dealing with now. The engine has new injectors, plugs, fuel pumps, filters and has been timed according to Ford procuders.
3. I used an OBD1 tester and got a 63 c code which the manual says: Throttle Position (TP) circuit fault, below min voltage.
4. Using my Fluke meter, I tested Primary voltage wire, which in my case is a Tan wire that may have a white stripe. This tested at 4,97V KOEO that is within specs. The secondary voltage (Green wire) was about .43V and did not change as I manually moved the throttle thru it's full range of motion. I repeated this test several times with same results.
5. I checked the 3rd wire for ground ( Black wire with White stripe) continuity back to the negative battery post and it was solid.
6. I thought I may as well check for "Continuity" between the Green wire and ground....nothing. and I got the same results between the Green wire and Black wire.

I'm probably going to get another TPS and see if the TPS was defective. I don't suspect that is the problem. I thought it "might" be the computer; however, I would like to get some second and third opinions before I start digging a deeper hole.

Thanks in advance!

 

Do you still have the old throttle position sensor? I would test it for a comparison.
Dying when being placed in drive or reverse, sounds like a transmission sensor related issues to me, but I don't know automatic transmissions so someone else will have to chime in on that.
How does your throttle plate adjustment screw look? A previous owner could have moved it, mistaking it for an idle adjustment screw. The idle air control valve is what actually adjusts the idle.

 

That is low for a base measurement and doesn’t change when opening the throttle? I’d say that the sensor isn’t installed correctly as in the TPS tabs are on the wrong side of the throttle body tabs so nothing is happening when the throttle is opened. To install the sensor you should have to slightly rotate it to get the screws installed.

I replaced the 302 in my F-150 with a 351 and reused all the old sensors and sending units. No need to “fix” something that isn’t broken.

 

My4Fordtrucks
Your response may be spot on. I remember having some some issues trying to install the TPS. I already had the engine/trans installed in the engine bay when I installed the intake manifold and throttlebody which limited access and visibility. When you suggested the TPS should be installed and rotated slightly to algn the screw holes would apply a certain degree of engagement and preload on the TPS that should increase the return voltage AND idle speed. In addition, the correct engagement would li increase the voltage reading when the throttle is moved ny hand thru its' operating range.

Thanks for the insight. I will try this first thing in the morning. In additon, thanks to all those that took the time to review my problems and respond.

 

Well, as it turns out, "My4Fordtrucks" was correct. I looked at the TPS closely this AM and noticed the "keyed" plastic tabs on the inside of the TPS could be manually rotated to put them in a position where they would not engage the metal blade of the throttle body. When I carefully rotated the plastic tabs on the TPS back in the opposite direction I could get the TPS to engage the metal blade on the throttle body at a very slight angle and then rotated a few degrees to align the screw holes with some extremely slight resistance. After bolting the TPS into position. I rechecked the volts with my Fluke meter. I got 4.9V on the Signal Voltage, 1.2V on the return voltage at rest, which went to about 3.6V as I manually operated the throttle, then back to 1.2V. I repeated this thru several cycles.

I started the engine which sounded like other F150s I have been around (my first F150) and I was able to put the trans in D,R without it stalling. YIPPEE!! Apparently, my Super Power is the ability to install something incorrectly. Anyway, my thanks to My4Fordtrucks and Soup Bean.