fuel pump going out? Options

[MonsterBOX]

ok first i had 150miles per tanks...added fuel injector cleaner and for some odd reason got like 300...car drives fine all the time until yesterday when i turn it on...when in neutral the rpms go from 500-1500 and move around in between like crazy...when revving the engine, throttle is very very sluggish and it feels like im being kicked cuz the engine jolts and sputters...car runs fine in upper rmps but on lower rpms it is very very jolty as if there is not enough fuel flow to the engine, when driving the car seems to drive like it has a flat as if its gripping the road like crazy and doesnt want to coast at all....the tranny seems fine and there no knocking or anything in the block, temps r fine, air intake fine, no water in the engine i dont know whats up any ideas??