i had the same problem whith my J30 (BTW J30's Rule) and i know the solution. it is gunk built up in the fule filter. if you take the fule filter off you should be abel to blow threw it whith no restriction at all (use a rag to blow threw so you dont inhale gassoline + there are arrows on the filter showing witch way the fule goes so blow that way) if there is any restriction then replace it. you have fule going threw it at like 30 P.S.I. so it still gets threw and the car runs. when restricted you get that problem. if it is ok and is clean the do what the other posts say.