I'd planned on changing the oil before going back to recheck emissions. I want to correct the rich mixture before changing the oil again. Would you change the oil first then (I don't smell fuel in the oil at this point)? Any suggestions on what to look at for the rich running condition? All the tune-up parts are new and the timing is 5 degrees with the vacuum removed (can't get it to 0 degrees as the distributor reached the stop). The idle is a bit rough and the idle mixture screw when fully leaned will not stall the engine.