Alright my CEL light came on yesterday after getting gas and went to autozone to get the code. It was the P301-cylinder 1 misfire detected. It runs fine with no sputtering or anything. So they reset the code. Then after a day it came on again and I talked with my dad who is manager of a car shop and he said that it can detect when dirt or water runs through and causes it to misfire when really nothing is wrong. I put fuel injector cleaner in it and reset the light. Hopefully it will not come on again. I just had it fully serviced 2 months ago and the oil was just changed a month ago at my dad's shop so I know it was actually done properly. The car only has 38K on it so nothing big should be broken at this point. I would think. I trust my dad knows what he is talking about and wouldn't let his daughter drive around in a death trap or something but I wanted to post to get others opinions.

 

A misfire in just one cylinder is probably not from bad fuel. A dirty injector is possible although not that likely. Also the spark plug and coil pack on that cylinder should be checked, sometimes the coils will go bad and you might or might not feel anything different.
If the problem persists a compression test would be a good idea to rule out (or in) any internal engine problems such as a burned valve.
What is the car's history, are you the original owner or did you buy it used? Is it now, or has it ever been modified?

 

He didn't really think it was bad fuel but his reasoning was that when water or dirt passes through it could read as a misfire when it actually isn't misfiring at all. So in order to rule that out he suggested the cleaner. I bought the car used and have only had one issue with it since I bought it a year ago and that was something with the power train broke a couple months after I bought it. As far as I know there have been no mods made to the car although I do believe the guy who had it before me enjoyed racing it since he traded this one in for the new STI model. It has been a day and a half since I put the cleaner in and have had no signs of the CEL so far. I don't want to count my chickens before they hatch. Also I just moved from the Midwest (Nebraska) to the South (South Carolina) and I don't think the car particularly cares for the change in climates at all. Apparently it doesn't like the humidity we have here.

 

Well good luck. I'd suggest that you take the car to a local shop that is familiar with Subarus and let them go over it. They will be able to determine whether it has been previously modified and returned to stock prior to being sold (this is very common), and they can also alert you to any existing or potential problems. For shop recommendations, check in your regional forum here and also at www.nasioc.com

 

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