bubba09baysoxCommunity MemberMarch 10, 2022 at 7:37 pm
A month ago my car was running lean and also was leaking coolant. I took it into the dealer where they fixed a both the lean code (CAM cover) and coolant leak (water outlet housing). After those fixes they recommended new spark plugs because I’ve never had them replaced before and they said they should be replaced every so and so miles and I’m over 100,000 so I agreed. After I picked it up from the dealer I noticed while driving on the highway at about 60ish the engine would sputter a bit every now and then. This has been an ongoing issue for the last month and I didn’t think much of it because the sputters were mild, until today my car had pretty bad jerking and my engine light was going off and it read that there were misfires in cylinder 1. I made an appointment with the same dealer but my question is my catalytic converter has been bad for a couple of months now, dealer said it was clogged and also the check engine light has been on for the cat (P0420) but I’ve put off having it fixed because I don’t have the money now. Is this new misfiring most likely due to the dealer messing the installation of the new spark plugs up? I worry they’re going to blame it on the cat and tell me to get that replaced but my catalytic converter light has been on months before and the sputtering never happened until right after the new spark plugs.
Year: 2014MSelleenAdministratorMarch 10, 2022 at 7:41 pm
When changing the spark plugs, you need to remove the ignition coils or wires and sometimes they can get damaged if they are old, even if you do nothing wrong. A faulty ignition coil could therefore cause the misfires on cylinder one.
If you drive too far with misfires, it can result in either a false P0420 code or the misfires can even damage the catalytic converter. I would try to fix the misfires first, then clear the codes and drive for a while
Read more: https://mechanicbase.com/trouble-code/p0420/
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