Strange things are happening

I purchased a 1998 Intrigue about 4 months ago. It had about 72,000 miles on it so I assumed it wasn't going to give me any problems. Boy was I wrong!! One day it stalled on me, on the highway, in the express lane! I had plenty of gas, figured it was just a fluke. Then it started happening daily. It's when I'm driving fast, driving slow, full tank, almost empty tank, the circumstances are never the same. I brought it back to the dealership, they checked it out and couldn't find anything. I then took it to my own mechanic, paid a fortune and he came up emptyhanded as well.
I changed the fuel filter,thinking maybe it was clogged, it was nasty! But it didn't help. Now, it's having trouble switching gears. I floor it and the engine revs but it doesn't go anywhere. Or I'll give it just a little gas and the RPMs jump up to 4500 and the car bucks. I'm at a loss. I've passed my 30-day lemon return period. What can I do??? Replace the fuel pump, or set it on fire!?!? I'm desprate. If it stalls in the winter on an icy highway, I'm a gonner!:banghead: None of this adds up but if anyone has a solution to a part of the problem I would greatly appreciate teh help.

Are you getting any MIL codes?

No, there are no codes. I was reading another post that had similar problems and it was resolved by replacing the crankshaft positioning sensor. I guess I'll try it.