Hi All,
My driveway was recently graced by a 2008 AT 4WD FJ Cruiser with over 230k on the odometer. While diagnosing a catalytic converter malfunction, I noticed that the driver's side bank had NGK plugs installed, but the passenger side bank was equipped with Denso plugs. My understanding is that many FJCs rolled off the assembly line this way, so I can only assume the previous owners never replaced the spark plugs.
I would estimate the spark gap on those plugs to have been 0.15" when I pulled them from the engine. I replaced them with Denso copper plugs. On the bright side, the new plugs seem to have cleared the catalytic converter codes.
My question is this:
Should I replace all of the coil packs due to the extended interval that the engine ran with spark plugs gapped greater than spec? The extremely high resistance of such a big air gap suggests that the coil packs pushed more voltage than normal in order to generate spark, putting unusual thermal stress on the ignition system. The previous owner said that he had replaced the battery and alternator a couple of years ago, and that makes me think the electrical system really suffered due to the lack of spark plug maintenance. The idle has an intermittent miss, but I can't identify which cylinder is the culprit. I ordered six Denso coil packs today, but I'm not sure if I should replace them all and sleep easy, or if I should try to diagnose the original coil packs, replace only the bad ones, and return the extras.
This is my first Toyota, so any advice/suggestions are welcome and appreciated.
My driveway was recently graced by a 2008 AT 4WD FJ Cruiser with over 230k on the odometer. While diagnosing a catalytic converter malfunction, I noticed that the driver's side bank had NGK plugs installed, but the passenger side bank was equipped with Denso plugs. My understanding is that many FJCs rolled off the assembly line this way, so I can only assume the previous owners never replaced the spark plugs.
I would estimate the spark gap on those plugs to have been 0.15" when I pulled them from the engine. I replaced them with Denso copper plugs. On the bright side, the new plugs seem to have cleared the catalytic converter codes.
My question is this:
Should I replace all of the coil packs due to the extended interval that the engine ran with spark plugs gapped greater than spec? The extremely high resistance of such a big air gap suggests that the coil packs pushed more voltage than normal in order to generate spark, putting unusual thermal stress on the ignition system. The previous owner said that he had replaced the battery and alternator a couple of years ago, and that makes me think the electrical system really suffered due to the lack of spark plug maintenance. The idle has an intermittent miss, but I can't identify which cylinder is the culprit. I ordered six Denso coil packs today, but I'm not sure if I should replace them all and sleep easy, or if I should try to diagnose the original coil packs, replace only the bad ones, and return the extras.
This is my first Toyota, so any advice/suggestions are welcome and appreciated.