Random Misfires

[KnifeyMcShanker]

Hey, I posted about this a while ago and forgot about it because the problem seemed like it resolved itself after a while, but unfortunately it's come back.

 

My engine will rarely throw a misfire code on cylinder 1 and 3, and it's happened like once on 2 and 4. I'd say 95% of the time it's 1 and 3 though. It happens once every 200 miles or so and only ever happens when I'm driving on the Highway (usually on my way to work, it's about 30 miles.)

 

I've heard a bunch of different recommendations, some people say it sounds like misadjusted lifters, a guy I work with thinks it's a knock sensor, someone I know thinks it's the combination of my short ram intake and the 2.5" catback exhaust I have.

 

So what do you guys think it could be? I'm thinking I may just try the shotgun effect and replace everything that MAY be bad and hope it works, as long as it's nothing too expensive.

[autoboty2k]

It would not be the lifters unless they are sticking. The lifters are not like Honda lifters, Subaru lifters are hydraulic and run off of your oil pressure. The only way to adjust them is to remove a metal shim inside the bucket of the lifter and measure with a micrometer. When you get that measurement, you then change shims according to the specs.

 

You may be getting a misfire from a bad coil pack, also maybe try changing plugs if you havent done so in the last 30,000 miles. It could be possible that with mods, that you are not getting the right fuel. I used to have misfire codes every time I would fill up with regular, but as soon as I would switch to premium, the codes would stop. Try getting the freeze frame data so you can see when the misfire is happening, rather at acceleration or just plain cruising. Just start with the simple things, try differant gas, if it comes back change the plugs.