Dodge Ram van stalls

I have a 1997 Dodge Ram van that intermittently stalls. It is fine when I start out in the morning. It is only after I have been driving, park, then drive again during the course of the day that the van tends to start stalling when I come to a stop at a light. Usually, it starts right back up, but lately it takes several tries for it to start up again. It sometimes happens when I make a right turn, and the engine shuts down and I have to coast a short while to get to the side of the road so that I can put it in park and try to restart again. When it stalls, the red oil light comes on, and the oil gauge needle goes down. When the van starts acting up, it tends to feel like it rides rougher, and I notice that the steering wheel creaks or groans when I turn the wheel.
I have taken the van to several different mechanics and no one can seem to replicate the problems I am having or are able to make it stall (but I think they are only taking it out one time to test). I have had the catalytic converter replaced and a tune up done. I am getting frustrated because I have a fear that I am going to stall and get stranded somewhere, but I can't get it fixed because no one can find a problem.