1997 Dodge Dakota killing out

HI, my dodge dakota has been killing when it gets warmed up, it drives fine down the road but when I slow to turn onto a street or into a parking lot the oil pressure drops very low (low enough to where check engin light comes on sometimes) and it kills, sort of fades out really.
I started useing fuel additive and that helped for awile but it has started killing again. I am about to move back to my home state next week which is a 1,600 mile drive so I need to get this fixed.

Thank you