It could be the plugs. Even though they are new, they may have fouled. The loud backfire was most likely the result of a build up of fuel. I hate to say it because I can't be 100% sure (not being there), but recheck spark to all plugs to make sure it is a hot snapping blue spark. Make sure none of the wires got mixed up going to the plugs. If the spark is orange, white, or something other than blue, and isn't arcing between the plug and electrode, the plug is most likely bad. (I don't want to suggest spending more money on plugs if you don't need to.) If you do get new plugs, get the OEM brand (AC)and type.
Saturday, January 22nd, 2011 AT 10:34 PM