Cylinder 3 misfire code

[Petox4]

Hello all,

About 9 months ago the CEL popped on, so I took it to the dealer and they said it was a P303 code...misfire on cylinder 3. They could not duplicate the problem and cleared the code and sent me home. Everything was fine until about 2 months ago. The CEL popped on again...same code...couldn't duplicate problem....sent me home. Well, it popped on within a couple of days. Back I go (this is getting expensive at $56 a pop) and this time they said it could be caused by a sticky valve which stays open just a hair too long or something at higher rpms, and to fix it it would be like $1500. They didn't give me exact details. Well, they turned it off again, but it was back on the next day. This time I was at a stoplight and wasn't going anywhere when it turned on. This time I had AutoZone check the code, and it was the P303 again. The guy felt sorry for me and let me clear the code while he wasn't looking. It was off for a few more days, but the CEL came back on again while at another stop light. I have noticed since this whole P303 started that my subie doesn't like to accelerate up hills very fast (like getting on the highway). It takes a while just crawling up the hill and once I'm over 30 or 40 mph, it seems to be okay. I just had the fuel filter replaced about a week ago and it is a lot better, but definetly not normal. Sometimes it is okay though. Could this be related to the P303? I have not felt anything like a misfire and the engine runs great. I am just really frustrated by the CEL being on all the time and am wondering if there are some other things that could be going on to cause a P303 code. There have never been any other codes with it. Thanks! BTW, I have a 1997 Subaru Legacy Outback 2.5L with 125K. I also have high milage oil in the car and use midgrade gasoline.

[Adnan]

Hi,

 

I had a misfire code on my '96 once but after that she ran fine. I started checking and was very surprised to find that the spark plug was loose, as in just tighter than finger tight. I checked the rest and while thery weren't loose they didn't seem to be tight enough.

 

Easy enough to check and if you're lucky, that might be all.

 

Regards,

Adnan

[nebmaster]

Check your spark plugs, wires, and clutch pack for a possible short. Get the car into a dark garage (or wait until night...) and have an assistant run the engine throughout the RPM range and look really close for any current leaks. This happened last summer in my 96 with a 2.2L, one of the wires had a small crack in the bottom of the boot leading to the coil pack. Unfortunatly, my coil pack was also fried by the time I figured out what was wrong, but after I replaced the wires, coil, and spark plugs (just for good measure...) the problem dissappeared. Best of luck