Help! 1991.5 W250 12v. Idle issues

[CumminGitThis]

Trucks driven and ran great for me up until recently. Went out in town and when I put it in reverse on a slight incline, the oil light came on and the idle dropped low. Parked the truck and went about my business. Truck starts great, no issue there. Park and neutral is fine. Only time I have a problem is when the truck warms up, then while I'm in drive or reverse with foot on the brake or barely any throttle, she sounds like she is going to stall. Recently changed the fuel filter, but I'm not too sure that'd be the problem since it starts and runs great until it warms up. Any suggestions? Fairly new to the diesel world so bear with me.

 

[cerberusiam]

Check the idle adjustment and make sure that hasn't backed off. If you cannot compensate with the idle adjustment or to has to go too high to keep form stalling you could have a problem with the TC or the pump needs some work.

 

[CumminGitThis]

Throttle has been adjusted previously and ran great. I don't have an issue with the idle until the truck warms up. After that, it starts bogging down like it's gonna stall

 

[cerberusiam]

When the engine warms the KSB is taking timing away, you need to check timing on the pump and possibly go thru it. There several things internally that go wrong and cause it to stall. ULSD is not kind to pumps that have not been updated.