Bad coil question
- Thread starter SmokeyBear
- Start date
Ford guy here, unless the coil is really hard to get to, do it yourself. It is a really easy repair on my 2 fords that have coils. On the 3.5L NA 09 Flex in my sig it will take 40 minutes for a coil on the side facing the firewall becaus it is under the intake which you have to remove. If you feel comfortable replacing the plugs, go ahead and do that as well if you have not done so yet. On my Mustang it takes a few minutes to replace a coil. The plugs on the other hand are a nightmare, but that is another topic. Watch some youtube videos specific to your car and take your time.
Depends on vehicle and year.
As I mentioned before, my '02 F150 with the 2v 5.4 just had it's first bad coil in over 200,000 miles.
My brother in law's '04 F150 with the 3v 5.4 had 7 bad coils (3 OEM, 4 aftermarket replacements).
He had 3 bad coils at once that fried his catalytic converters, but that is because he kept driving with mis-fires for at least 10,000 miles. He also had original plugs @ 150,000 miles, and the plugs were shot.
My bad ignition coil took out the cat within 25-50 miles of driving. Un-burned fuel must go somewhere & that next spot is the, hot, cat. I would not want to gamble by driving, any mileage, with a bad one anymore. One way to get around this I suppose is any check engine lights you best be pulling over. Have a bluetooth code reader w/you & if it's a coil then have it towed from there. It can get expensive & inconvenient quick. How about when the second one goes out? Keep running the other old two? Third one fails... keep running the last old one? 
Sell the remaining good ones on ebay to lower the cost. If there's anywhere to penny pinch it's not here.
Sell the remaining good ones on ebay to lower the cost. If there's anywhere to penny pinch it's not here.If you can unplug the injectors, just unplug them one at a time until you find one that doesn't change how the engine runs. That'll keep your cat from dying. This only works if you have a bad misfire on a single cylinder and accessible injector plugsMy bad ignition coil took out the cat within 25-50 miles of driving. Un-burned fuel must go somewhere & that next spot is the, hot, cat. I would not want to gamble by driving, any mileage, with a bad one anymore. One way to get around this I suppose is any check engine lights you best be pulling over. Have a bluetooth code reader w/you & if it's a coil then have it towed from there. It can get expensive & inconvenient quick. How about when the second one goes out? Keep running the other old two? Third one fails... keep running the last old one?
Good workaround if you must drive to the repair shop or home in a pinch. That very well could've saved my cat had I thought of that.
Last edited:
Ford started incorporating Primary IC functions into PCM's with the transition to DIS (Distriutorless Ignition System's), Starting with Waste Spark then transitioning to COP on some engines, Modular V8's started out with Waste Spark then transitioned to COP.
Oh wow! I wouldn't have figured it was that long ago. Thanks for the info, I'll keep that in mind.
