ckeck the fuel pruessure after you shut it of and watch it for about 15 min. if it drops more than like 5 or 6 psi you have a bad fuel pump. It sounds like your losing fuel pruessure as the car sits. That may be why its a little hard to start after sitting and keep running - your fuel pump is trying to re-build the required fuel pruess. to run - and once it does it runs fine