morrian14 Posted March 14, 2015 Share Posted March 14, 2015 (edited) About a year and a half ago I purchased my 2002 outback with 130k miles on it. The previous owner told me that it was going to need O2 sensors put on it, which I was fine with. Because of this, the check engine light stayed on. When I went to get it replaced I was told by my mechanic that the catalytic converter was also going to need replaced. Awesome. It ended up still passing emissions because neither were super bad so I decided to drive it until I could get enough money to replace it. On one fateful morning, my car gave up on life and the check engine light started flashing for just a moment and then shut off. I could barely get it to go 20mph and with some prayers it ended up safely at my boyfriend's house. Using the OBD II, we came to the conclusion that the catalytic converter was completely clogged and caused a misfire. He replaced it for me and both O2 sensors. The car was running very nice following this. The only problem I had otherwise was an oil leak, which was very slow and had been going on for a while. After a month or so I was driving down the road and BAM the muffler rusts off. Because of the way the new parts are sold I was forced not only to get the new muffler but also the resonators between the catalytic converter and the muffler. My boyfriend fixed this a few days ago and the car seemed okay. Around the same time, it started to idle really rough upon start. My boyfriend told me it could be because of the ridiculously cold weather and it might be okay. Today it was doing its new rough idling thing at start and I crossed my fingers and headed off. To my wonderful surprise, the check engine light flashed for a brief moment after accelerating from a dead stop. The car wasn't running nearly as awful as the last time it had happened. It was idling rough but didn't have a greatly noticeable drop in power. I know that a flashing check engine light means a misfire. I honestly don't know what to even think anymore. My dad rushed over and drove the car around. Light never came on and the car was running a little less rough (probably because it was hot now though). General information on car: -Mostly new exhaust system -Idles rough, especially when cold -Check engine light flashed very briefly -Some drop in power -Very slow oil leak that probably isn't related What has been mentioned to be the problem: -Water in fuel -Bad EGR valve -Bad spark plugs I'm not exactly an expert on cars. I am more trying to get information for my boyfriend to help fix my car. Any ideas would be great. Thank you. Edited March 14, 2015 by morrian14 Link to comment Share on other sites More sharing options...
AdventureSubaru Posted March 14, 2015 Share Posted March 14, 2015 (edited) Bad plug wires. Especially if it is worse on cold/wet/humid days and better on warmer dryer days. Best for Subaru is NGK or Subaru OEM. Usually a good idea to do spark plugs at the same time. NGK brand again. Both are routine maintenance that will make the car run poorly/misfire if they are not changed at proper intervals and begin to fail. Check for oil in the plug wells and clean it if it's there. There are little rings that come as a set with valve cover gaskets that solve this if oil is present. Edited March 14, 2015 by AdventureSubaru Link to comment Share on other sites More sharing options...
morrian14 Posted March 14, 2015 Author Share Posted March 14, 2015 If that is the issue that would be great. I had asked my boyfriend about doing the spark plugs and wires right before inspection last summer and he said they looked brand new and I could probably just do them another time. They are NGK brand. The previous owner only ever took the thing to the dealer when things needed replaced. He even gave me a pile of receipts from every single repair. It was a really well cared for car before I got it. I think what I might do is rent the OBD II, see what it says. And while I'm out just buy replacement wires/plugs and also buy that additive to remove water from the fuel. That's about all I can do at this point. Link to comment Share on other sites More sharing options...
Stevo F Posted March 14, 2015 Share Posted March 14, 2015 Still could be an O2 sensor. Our 2005 OBS had the check engine light on an off a few times then finally stayed on all the time. I have a code scanner which told me it eas the front (upstream O2) sensor. In our case, the car still seemed to run OK, but in many cases, the car will perform poorly (ropugh idle, low MPG;s) as without a functional O2 sensor, the ECUre tunes the car into a default limp mode. I ended up having to have our mechanic change the sensor because someone had apparently cross- threaded the last one. New O2 sensor is in and no more CEL. Incidentally, if you replace a Subaru O2 sensor use Denso brand as these are OEM. Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 14, 2015 Share Posted March 14, 2015 Spark plug and wires are the first thing you should have changed way back when the light was flashing before. NGK brand on both and you'll be running smooth again. Link to comment Share on other sites More sharing options...
morrian14 Posted March 14, 2015 Author Share Posted March 14, 2015 I just had both O2 sensors replaced two months ago along with the cat. With one of them bad, it was a constant light on as opposed to the blinking I got today. I'm not sure just a bad O2 sensor would cause a misfire. That's why I hadn't suspected the O2 sensor again. Link to comment Share on other sites More sharing options...
lmdew Posted March 14, 2015 Share Posted March 14, 2015 Get the codes. Even if the CEL is not on the codes will be stored. Most Auto parts will read them for Free! Link to comment Share on other sites More sharing options...
morrian14 Posted March 15, 2015 Author Share Posted March 15, 2015 After reading up more, I definitely think it is the spark plugs/wires. I'll probably still run the code just to be safe but it'll probably just say an engine misfire. I bought all new wires and spark plugs today, will be replacing them tomorrow. Thanks for the help everyone! Link to comment Share on other sites More sharing options...
AdventureSubaru Posted March 15, 2015 Share Posted March 15, 2015 Autozone, O'reilly and advance auto at least will scan the codes for free. Napa too I think Link to comment Share on other sites More sharing options...
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