By Mario Rojas, Great Bear Automotive, Miami, FL.
I received a work order for a misfire and MIL concern on a 2009 Chevrolet Suburban 5.3L. As I’m walking out to the parking lot, a plan of attack is already contemplated. I usually will follow the same exact plan of attack when it comes to any misfire. As I see it, there's a fork in the road on a misfire strategy. Road number one leads us down the path of a mechanical failure/cylinder wash possibility. Road number two leads us to all of the other possibilities; air/fuel concerns, ignition, electrical, etc. In some cases, the injector of a misfiring cylinder may be disabled, so as to prevent cylinder wash in the case of weak/no spark conditions (something I always keep in the back of my mind).