1997 Oldsmobile Bravada engine misfires in Morning and some

The fuel pump is working and I have spark at the ignition coil. Two days ago wouldn't start but was trying to. Showed 1/4 tank of gas so I added about 3 gals and it findly started but was missing when reeved up. It would start up every time after that. Two days later after sitting at the body shop it want start even though it shows 1/2 tank. It has been missing in the morning for about a year, but after I would kill it a coupel of times it runs great all day. I had put it in the shop a year ago for this problem and they put a new fuel pump and a fuel pressure regulator and an intake gasket. Ran ok for a day or 2 and the the same problem. It has failed to start once until this time, but started later that afternoon. I ran some bearmans b12 in it before this last tank of gas.