Hello there,

My Outback started running a little rough, and the check engine light would periodically come on (which also made the cruise control not work, and the cruise light to flash). Sometimes I would be driving down the freeway with the cruise on, and I hit a small bump, which made the check engine light come on and the cruise to stop working. I took it to the auto parts store about a month ago, and there was only one misfire (I thought it was #3, but I could be mistaken. It recently got worse, so again, I took it to the auto parts store to do a code scan, it came up with P0301, P0302, and P0304 which is misfire in cylinders 1,2, and 4. It's probably worth mention that my Subaru is past due for it's 60K Service.

 

I also just changed the plugs, with identical NGK's which made no difference whatsoever. I did some browsing, and it seems there are a few common culprits: Ignition wires, Coil, Timing belt?

 

I am going to try running the engine in the dark to see if I can see any sparks on the ignition componets, once I get that knocked out, I will update.
 

Any suggestions, or ideas will be recieved with much grattitude!

 

Thanks!

 

Edit: Sparks observed by the wire boot on the coil side. I am gonna go pick up some plug wires and dielectric grase, and see what happens.

Edited June 30, 201312 yr by hancho3

Spark by the coil is probably the cause. Sounds like its time for some new wires. Subaru OEM or NGK brand are the only ones people here recommend.

Well, because of my need to get on the road, and it being sunday, I went with the only ones they had at my local auto parts store. Here they are: http://www.oreillyauto.com/site/c/detail/IDW0/40475/02815.oap?year=2006&make=Subaru&model=Outback&vi=1432741&ck=Search_plug+wire_02815_1432741_3689&keyword=plug+wire&pt=02815&ppt=C0334

 

I guess I will replace them again with OEM if need be. The cap that covers the hole in the valve cover doesn't seem to fit snug, nor did the wire end snap on to the plug as noticibly.

 

I got 2 done, and started it, and it was already running better. Gonna go hit the other 2 now.

When is the last time your front 02 sensor was changed?

Does the symptom only occur when the engine is warm?

If so, this points to the front oxygen sensor needing replacement.

My 2001 Forester seems to need a new one every 40k miles.

Closure detail beacuse I work a service desk type job:

 

I started my car with the hood open, and could immediately hear the snapping sound of arcing electricity. 3 cylinders were misfiring beacuse they were all arcing on the #3 wire. Probably not good After replacing all the spark plug wires, the car started running like a champ. Totally stoked that it was only the wires. I purchased non OEM wires (linked above), which I know you guys frown upon, but they seem to work (mostly).

 

3 resons why I regret not buying OEM:

• The boot is standing a good 1/8-3/16 from actually sealing on the valve cover.
• The wires didn't seem to snap on to the plug as well as the OEM wires did either.
• The plug wires aren't numbered (no big deal, but hey why not?)

 

Anyways, problem solved! Thanks!

You may soon have a recurrence of misfire problems due to the poor quality of the wires. Might want to order a set of NGK wires, or get a set from a dealer. Even if you just keep them around for future use, it would be a good idea to have them.