Will Driving 100 Miles With a Misfire Damage My Car?

Question

Background:

I have a 2002 Dodge Dakota Quad Cab slt with 4.7L Magnum V8. My check engine light came on when I was at work. I then drove 20 miles home to my house, pulled out my scan tool and discovered I had a misfire in cylinder 7. Next I cleared the code and drove about 20 miles the next day and at the very end of the day the check engine light came back on same code.

Troubleshooting Work:

I switched the coil packs on cylinder 1 and 7 cleared the code and let the car idle. The misfire in cylinder 7 code quickly reappeared. Next I felt the fuel injector and verified it was working. Finally, I tested the electrical system and found the coil was getting power. Now I have narrowed down the issue to the spark plug. Unfortunately, my spark plug removal tools are 10 miles away.

Question:

By the time I get to the my spark plug tools I will have driven the car 50 miles plus sometime idling while troubleshooting. If the spark plug is not the issue and I have to take it in to a shop I could potentially drive it 50 more miles. Will this damage my catalytic or 02 sensors? Or any other component?

Summary:

Will driving my 2002 Dodge Dakota Quad Cab slt with a 4.7L Magnum V8, 100 miles with a cylinder 7 misfire damage my catalytic or 02 sensors? Or any other component?

Thanks,

• Joel

Answer 1

You should be fine.

Though I would recommend unplugging the connector to fuel injector #7 to minimize the amount of unburnt fuel that makes its way to the catalytic converter.

Answer 2

While you have that spark plug out, i would highly recommend doing a compression check on that cylinder while you have everything off/out.

Answer 3

I know it's a little late, but for anyone looking with a similar condition. Chrysler engine software will shut down the injector on a missing cylinder once it meets the threshold to turn on the MIL (malfunction indicator lamp, check engine lamp) If the misfire is severe enough to damage the cat, the check engine lamp will flash. This goes for almost all manufactures. Extended driving with a misfire may cause premature catalytic converter failure. As far as the 4.7, they have an issue with valves and seats along with the 5.2, 5.7, 5.9, 3.7, and 3.6. "If a Ford has a misfire,it's a coil. If a Chrysler has a misfire, its a head!" If plugs, coils, and compression look good, you would want to do a cylinder leakdown test. This will usually show a leaking exhaust valve. 43 years as a technician, 7 years as a shop owner. 14 years with Chrysler as a Powertrain, Chassis, and Electrical Master Technician.