Stalling

There are many reasons that you might be stalling out. One things to look at, I am including a diagnostic walk through for your situation and it wil get into this, it obstrucitons in the intake and exhaust. Vehicles with your mileage acan often have a catalytic converter fail internally and collapse in on itself and clog the exhaust. Another common issue is fuel preussure problems. To quick check, this does not mean it is not in need of replacement, the converter whack it with your hand or a rubber amllet and listen for loose material.
Use the link below for the diagnostic;

https://www.2carpros.com/articles/engine-stalls

I thought the walk through did have both mention of crankshaft and camshaft position sensors. Thanks for pointing that out Marty, I will look into that. Yes, especially the crankshaft sensor should be suspect. Your truck is an OBD 1 so it can be scanned for codes, but not always easily. Try to get Advance or Auto zone to pull trouble codes and the crankshaft sensor should come up if faulty. If it does not come up it does not mean it is not failing intermitantly though. You should price on out at www. Roackauto. Com. You would not believe how cheap this place is despite selling well known name brands. They are a closeout only dealer and their stock changes rapidly so it is worth check ing everyday. I got a near $200.00 wiper motor for $40.00. I could have gotten an even cheaper one but I wanted the one made by Cardone as I was more fmailiar with the re-manufacturer. They sell new parts to as a position sensor will be new.