Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Misfire mystery - 2005 Subaru Impreza Sedan WRX

My car has a misfire on cylinders 3 and 4. I’ve replaced the ignition coils which didn’t work, but when I swapped the injectors on the 3rd and 1st cylinder the misfire jumped to the 1st and second cylinder. Surely this is an injector problem? I ordered new injectors but they are on back order so while I wait a month to get them I figured I would ask the car community if the misfire could be caused by anything else. The engine struggles a little at low RPMs but pulls great after 3500-4000 RPMs. Also consuming an absurd amount of fuel.

Sure kinda sounds like leaking injectors causing a misfire at low rpm - so the codes - and then blowing thru it at higher revs. Your swap theory has me confused though. #3’s injector misfires in #1 - OK, makes sense. #2 only misfired after you swapped injectors on #1 and #3 ?? Huh?

You didn’t touch #2 but the misfire appears now on 2. Strange - Unless your sentence didn’t read correctly because you spelled out second cylinder and I read that as #2.

The actual codes would be helpful unless it is just P0301 and P0302 you are now getting. I’d check for fuel pressure at idles and running just to be sure it is within spec. I might even install a new fuel filter if you haven’t changed it recently. Crud in the gas tank from a skeezy station may have clogged both filter and injectors.

You were correct. Sorry for the confusion with the way I worded it. But yes, It originally misfired on cylinders 3&4, but when I swapped the Injectors on the 1&3 cylinder (injector from cylinder 1 into cylinder 3 and vice versa) the misfiring moved to cylinders 1&2. I haven’t checked the injectors on the 2&4 side, but the spark plug on cylinder 3 is very dirty for only 1,000 or so miles of use. The codes are P0301 and P0302.

Also worth noting I did order a new fuel filter as a backup.

I’m just trying to find out anything else I could try in case the injectors don’t fix the problem. I’ll admit I’m kinda puzzled why the misfiring jumped from 3&4 to 1&2 when I only swapped injectors 1&3, but the fact that it moved when I only changed the injectors leads me to believe they have to be the cause of the problem.