intermittent cyl3 misfire

*car was stored for 6 months. after plating and driving around for a bit, used some fuel treatment and filled up on 93...issue came up 2 days after*

So ive done tons of research and found that this is kinda common and that it can be due to any number of things. Last week it came up and i brought it to a shop to have it checked out (working and dont have time to work on it myself and potentially not have something to get to work with). They checked the plugs and they were fine, and then swapped #1 and #3 coilpacks to check if it was that (no oil on the boot..WOO no leaks there); everything was okay. As they put it back together the problem seemed to have gone away so i drove it around extensively to try and get it to misfire, monitoring my knocking, roughness and AFRs. Everything seemed to be okay up until this morning (3 days later) on my way to work, was was just cruising and, same thing again.

I was thinking at this point it might be the injector, being that when we pulled the plug out, it wasent soaked or anything; infact it looked like two ends of metal that shorted out.

Or would my best bet be to replace all 4 plugs, coils, injectors?

Also the guy told me something along the lines of not having enough oil pressure and that potentially causing a lifter to not open the valve enough causing the misfire..sounds plausible, but if that was the case, would'nt the misfire go away, and not something that stays an issue for a long period of time, and then is fine for a while aswell?

Anyone want to chime in?

Originally Posted by rad.rac3r

Also the guy told me something along the lines of not having enough oil pressure and that potentially causing a lifter to not open the valve enough causing the misfire..sounds plausible, but if that was the case, would'nt the misfire go away, and not something that stays an issue for a long period of time, and then is fine for a while aswell?

Anyone want to chime in?

This guy know NOTHING about Subaru's, or OHC engines the way it sounds. Your engine does NOT have lifters.

I get a #4 cylinder misfire at times myself. I have finally come to the conclusion that it is my injector. I keep resetting the code and am waiting for spring to do a turbo and injector upgrade.

posted in your other thread. do a leakdown to ensure its not a burnt valve, then move on to the simple fixes, like injector swap

Originally Posted by wurkenman

This guy know NOTHING about Subaru's, or OHC engines the way it sounds. Your engine does NOT have lifters.

I get a #4 cylinder misfire at times myself. I have finally come to the conclusion that it is my injector. I keep resetting the code and am waiting for spring to do a turbo and injector upgrade.

Yeaaa thats what ripemeat had mentioned in the other thread. Ill be doing a leakdown test within the next day or two

Originally Posted by ripemeat

posted in your other thread. do a leakdown to ensure its not a burnt valve, then move on to the simple fixes, like injector swap

Yea..kinda desperate for info. And thanks for replying. I reeeally hope its not a burnt valve..could that happen even without the ecu throwing a code for the system running too lean? i.e. it running just under the threshold for that code to come up?

burnt valves come from other reasons than running lean(too little timing, head wear). once its burnt it can show up only as a miss in that cyl. sometimes you won't get a cel until the car is fully warmed if its the right kinda of valve damage. i have my money on an injector being your issue, but doing a leakdown first may save you a lot of diag time if it is in fact an internal issue

Understood. Leakdown test it is. Ill keep you posted on what i find.

Might as well do it on all 4 cylinders while you are at it.

Was planning on it...ive had more trouble with this car then id like to admit -_-

And why not do spark plugs while you are in there. When the tech is done just hand him new ones to screw back in
Two for one

true true...was contemplating injectors aswell >.> may aswell overhaul while its apart and ill be doing it myself; swearing the whole way through ofcourse..

Injectors are separate/more labor.
Basically for a leakdown/compression test the coils and spark plugs need to be removed so while the tech is in there might as well replace them if it's time.