If it is one of the small allen drive bolts (5mm) that secure your coils down, if you can, get a 12pt 9mm socket and hammer it down over the old stripped bolt. Works like a charm everytime.
Just make sure you use a 12 point socket. At Sears they are around 4-5 bucks. loosen your 2 fuel lines up with 17mm wrench
if needed to access.