Yea I'm beginning to suspect the ignition, too. The behavior of the engine as it accellerates doesn't seem to be fuel related (the backfire and the fact that it's more of a stutter than a flat spot) I suspect that my spark plug wires might be bad (the spark plugs themselves are good, supposedly - I replaced them just last weekend) so I'm going to check them for arcing and continuity later this week. The cap is old, too- I'll check the inside for signs of arcing. Will post my findings of course....