1990 T4r auto/4x4/v6
Approx. 2 years ago trans and engine shop rebuild
Approx. 1 1/2 year ago had shop tune up

I am back and I do appreciate the comments and suggestions from YotaTech members!!
Within the past week replaced the accelerator cable and a tune-up; plugs and wires, rotor, oil and filter, air cleaner. Without removing the throttle body I did remove the ducting and clean the bore. Before adjusting the timing I marked the position of the distributor retaining bolt then used the jump wire T1-E1 and set the timing only to find the new mark is approx. 1" off to the original?
I should know better but while checking out a 'how-to' articles on U-Tube on adjusting rpm author pointed out a set screw on the side of the throttle body and described it as the rpm adjustment screw so I have been toying with the set screw and timing a bit but if understand correctly there is no rpm or idle adjusting screw so this may have been a mistake??

The truck runs fine until it has an episode where the rpm drops below 500 and stalls but I can start the vehicle up and funs fine until another episode.
Runs around 1200 rpm until the engine warms up then drops to around 6-7k, but then I can be sitting at a stop and the engine will stop. This a.m. started the engine and let it run at idle and all gauges were within limits and it ran fine until the engine warmed up and then the engine stopped running. I started up again and let it run and it ran fine, It sounded like it wanted to bog down when the temp was normal but it did maintain rpm and the engine remained running.

I have a great deal of knowledge when it comes to working on Pre-70 vehicles but when it comes to sensors, jumper wire to diagnose, and other bells and whistles I am at a loss.
Perhaps I can work out a swap with the seller???

Suggestions/comments appreciated.

 

Took for a couple of tests runs today and all appear fine, seems close and perhaps by tweaking either timing or air/fuel mixture will solve the issue?