Acast2705

How's it going everyone, My name is Aaron and I'm new to the fourms. I'm having an issue with my CEL. It popped on and got it checked out and got 'P0302 Rear rotor misfire detected' See my issue here is I don't know where to start. I know that usually a misfire is due to a bad plug or coil. And I know from expeirence that there is a performance loss when you have a bad plug or coil. I have an 04' Grand Touring 6-speed. The only upgrade is my K&N air intake. So just wondering if anyone can lead me in the right direction in figuring this out myself. I'd rather not take it to a machinac if I can do this myself.

Flashwing

Well, sounds like you already have a sense of where to start. The best is start small and work up from there.

Misfires do happen and they are most common in the rear rotor.

First step would be to check your plugs. If you've not changed your plugs in 20,000 - 30,000 miles it would be worth doing. Next would be to check the condition of your plug wires and coils. There's lots of information on coil failures. Make sure you're running 91 octane or higher as well.

If you do suspect your coils then you can spend the money for OEM replacement or an aftermarket upgrade.

Acast2705

I also forgot to mention. I have no loss in performance. With my truck a plug went bad and it ran like complete crap. But im not having any drop in performance.

Flashwing

Usually the only time you would notice a coil failure (or plug failure) would be in the leading position.

I actually drove around for what could have been 6 months to a year on a bad trailing coil. I never knew it was bad until it was replaced and suddenly the car felt a lot smoother!

If you check out the coil failure stuff, sometimes a sign is what looks like white spotting on the bottom of the coil. The problem is there's an arching that occurs with the coil and can cause it to fail.

Not always 100% accurate but it's a sign that's usually present when failure or near failure occurs.

Pulling your plugs will also show signs. When my trailing plug was pulled you could tell it had not fired for a LONG time as it was completly coated in carbon.