1996 RAM van v-6 3.9 Driving down the roadbetween full tank and half tank of gas runs fine, between half and empty it might run fine or it may not. It gets sluggish, won't pull itself, it might die and not start for awhile. Put injector cleaner in the gas it might be fine for 2 or 3 tank fulls then starts acting up again. any ideas Thanks MDS

 

You've got a problem in the tank. Either the fuel pump is weak or the pickup tube has a leak about half way up and is sucking air. Considering the problem is sometimes non-existent for a couple of tanks, I'd lay odds on it being the pump and not a pickup tube leak. Either way, your tank has to come out for the repair.