My car cuts off at 4000 rpm under hard acceleration and smokes black at tips and has a rough idle. It blows out fuses to the air pump. When I put a new fuse on and run it for a little bit, it seems to run fine til after a while it starts sputtering. When I park it blows the fuse out. WHat could cause this?

 

what year is your car? If its a 95 or older I would disconnect the Air Pump and see how it runs. Although I don't believe the air pump will affect how the car runs, because it is for emissions anyways

 

Yes that sounds like a completely different problem My air pump blew out and I just unplugged it but I in no way had any of the problems you have. Seems to sounds like something with your fuel but i could be wrong

 

went to a buddy of mine at a local chevy house. he hooked up a fule pressure guage. and read like 25 PSI at idle. when he would give it gas it wouldn't climb it would just stay there. i then changed my fule filter and it acted a little better.