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Chris, Auto Service Technician
Category: Car
Satisfied Customers: 12592
Experience:  43 years of automotive repair, Smog license
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Car started hesitating, got worse, now it idles rough, and

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Car started hesitating, got worse, now it idles rough, and just wants to dies out..hooked up a reader and it gave me a code that said the number 3 cylinder wasn't firing....but, under that it had a crapload of other would be causes....I installed a lot of aftermarket parts, and it's ran great, but now i'm wondering if I did something by doing this and it's now caught up...I've taken off the after market stuff, and reinstalled the original air intake etc...but it does the same thing. I did install a axle back exhaust, but didn't take that it possible it's the exhaust system I installed?

Hello and welcome to just answer. Your after market parts will not cause a misfire on cylinder # XXXXX You have a misfire due to an ignition problem, fuel injector problem, or low compression. The first thing you need to rule out is a compression issue, so do / get a compression test on all cylinders. They should all be within 25 lbs of each other. If # XXXXX is lower than the rest, then something is going on like a burnt valve or other mechanical problem. If the compression is ok, then try new plugs and maybe swap the #3 fuel injector with another cylinder. If the misfire moves to the other cylinder, then you will need to replace the injector.


I hope these tips will help you figure this out, and let me know if you need further assistance with this.




Customer: replied 3 years ago.

Thanks! I will do just that!

You are welcome Pete, and good luck my friend,



Customer: replied 3 years ago.

It was a bad plug. The electrode was burnt completely there something that causes this?...just concerned there's another problem brewing that may have caused it....or just defective plug?

Well it could have been just a super worn out plug or a cylinder that is running too lean. One thing I do recommend is to use the exact same OEM spark plug that the engine came with. Also add a bottle of fuel injector cleaner into the tank at your next fillup. That will help to keep the injectors tips clean.

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