I changed the spark plugs in my vehicle and it now sputters, hesitates, and backfires. I then changed the distributor cap, rotor, wires, and coil wires, and the vehicle is still doing this.
When problems arise after a recent service, the best thing to do is go back and check all of the work. Mistakes do happen, and other parts can get bumped during a service. First, proper wire routing must be determined, as this is common, and shares the symptoms you described. The correct firing order is necessary for a smooth-running engine. The area should be checked for any hoses that may have been bumped loose, allowing a vacuum leak. Have an experienced technician look over the vehicle, verify the work and track the source of your vehicle’s sputtering.