My 96 had been sitting up a while. I took it out to do the oil change and tune up. New plugs, wires, cap and rotor and new fuel filter. Air filter has maybe 3000 miles on it. I took it for a soon and it sputters and backfires whe, and when you first take off and when the RPMs drop when it shifts. At high RPMs it runs great and at idle it runs great. Could it just be crap from the ethanol sitting for a while? I added fresh gas but it did still have about an eighth of a tank of old gas.