P0301 Code
Thread Starter
Staging Lane
Joined: Jan 2018
Posts: 77
Likes: 0
From: Inland Empire, CA
P0301 Code I have a P0301 code that keeps returning but the car seems to have tons of power. There is some valve train ticking could that be the cause of the misfire? Is there a list of things that could possibly cause this code besides plugs, wires, and o2 sensors?
Have you pulled the plug to look at it? The coil, wire, spark plug, and injector can all be culprits. The o2 sensor should not be responsible for a cylinder specific misfire. One simple test that you can do (after replacing the plug because it is likely fouled) is to swap two plug wires on the same bank and to swap your coil packs from bank to bank. If your misfire code never returns, it was the plug. If your code moves to the other cylinder on the same bank, it was your wire. If the code moves to the cylinder on the other bank, it was your coil. If none of that changes anything you could start to suspect the injector or the valvetrain (rocker, pushrod, valve, lifter) for that cylinder.
Thread Starter
Staging Lane
Joined: Jan 2018
Posts: 77
Likes: 0
From: Inland Empire, CA
Update The code disappeared this morning with no other changes after freeway driving. Ordered new plugs and wires. Could the misfire be related to any valvetrain ticking? Not sure if my tick is exhaust leak or lifter/rocker noise. The car seemed to run well when I had the code...
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
Lifter or wrist pin. I hope for your sake it's a lifter though. Check your oil level, and you can try some sea foam in the case of the lifter. If it's a wrist pin though, you might just be SOL. That's a rebuild.
Try carefully pulling one plug wire at a time where the noise is loudest. If the noise stops or is significantly reduced, then it's probably a wrist pin. Running it low on oil can easily smoke a wrist pin. It's not good for lifters either.
Try carefully pulling one plug wire at a time where the noise is loudest. If the noise stops or is significantly reduced, then it's probably a wrist pin. Running it low on oil can easily smoke a wrist pin. It's not good for lifters either.
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
You can also pull the valve cover and see if the preload is still good on those lifters, or if there are any other significant mechanical problems in there like obvious wear or metal particles laying around. That would indicate a bad rocker, pushrod, lifter, or combination of those.
Give a good cleaning a chance to clear it up if you don't find anything upon inspection. You can use brake cleaner and engine flush to clean it. Only run the engine at idle, for about 5 minutes. Use the brake cleaner to spray directly down the pushrods.
Then change your oil and pray.
Give a good cleaning a chance to clear it up if you don't find anything upon inspection. You can use brake cleaner and engine flush to clean it. Only run the engine at idle, for about 5 minutes. Use the brake cleaner to spray directly down the pushrods.
Then change your oil and pray.
