My truck is stumbling (not an A-Body)

I have a 98 Ram 1500 4x4 with a 5.2L (318). Sometimes when I am driving very slow the engine stumbles badly. If I let off the gas it will idle so/so but if I give the gas a pump or two it excellerates like normal. I have also noticed a couple of times that when I am coming to a stop the engine will give a short surge and then idle properly. The check engine light comes on and goes off by itself and has been doing this for about a month. I had a diag done and nothing showed as far as error codes.

Anybody have any ideas?

Jack