From the sounds of it you could have a fuel problem. I would start with the cheapest item and work my way up to the more expensive. I dont know if you have done all of your prevenative maintenance but you diffanetly need to change those spark plugs if you havnt already done so. next I would go to the fuel filter, it could be cloged or dirty from bad or rusty gas. After that I would check my massairflow sensor this could cause all types of problems, even the ones your encountering now. Next check that fuel pan, you dont have to drop it you can go in through the trunk to take a peek. And last but not least get some one to check that fuel pump out.