Yeah u probably had a tad of unburt fuel when it backfired. How do your plugs look when u take them off? Black with soot? A redneck way to fix that is burning the tip wiith a propane torch then regapping them.
um..not really for spark plugs,but there like $2.xx each So there not to bad.I mean i bought the box(pack of 4) and was less than 11$ in all.
but I have to call ahead of time to get them shipped from the warehouse to the store only downfall in the ones I use..they have some matching ones forgot the brand but there like 1.xx each but Id rather stick with NGK.