I dont think it is the O2 sensor,but if you want to try, just unplug it and
see.You can drive just fine like this. Check the throttle switch
adjustment. It needs to be really tight,clicking  on and off quickly near
idle.If it is way off, your clutch function will seem different than in the
past.Dosent drive like it used to.Sounds like your new AFM has the
tantallem capacitor in it. Intermittant problems might be a loose wire, or
broken wire in the distributor. Maybe check the 3 little wires that enter
the distributor. Sometimes they arn't connected like they should be.Vaccum
hose?