well my dad bought the oil so I can't complain. Ill try Mobil semi syn. next oil change. Also have to drop into NAPA and get a different filter. Also are the K&N Filters good and has anyone tried STP Fuel Injector Cleaner? My 80 has a bad lag spot when accelerating and according to LCOOL its from a build up of dirt and junk in the fuel injecdtors. Just wanted to see if anyone has the same problem.