Rooster2 Posted June 20, 2011 Share Posted June 20, 2011 My wife reported that her Subie motor was running poorly. Upon checking it out, I could tell that it was not running on all cylinders. It was throwing a CEL, idled poorly, then stall, and lacked power. Upon restart, I revved up the motor a few times, and held the idle at 3,000 to 4,000 rpm, but it didn't run any better. A little later, ( 10 minutes later ) I started the car again. This time the motor ran well with power, and idled well, as if the ECU had reset itself. It seemed to drive alright as well. I then drove to Autozone to have the stored CEL code(s) pulled. Results were code PO303 for both cylinders 3 & 4. I pulled the pos battery cable, waited a bit, reinstalled the battery cable to clear the CEL. The CEL remains off, and the car continues to run well. Any idea what caused the engine to do this. BTW, the car had not been driven for 4 days. It sat outside and endured a couple of very heavy thunder storm rains during this time span. It is hard to believe that storms would cause this. Any advise and thoughts would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 20, 2011 Share Posted June 20, 2011 Hah I recall reading someplace that one of the model years for the outback had funky acting ECU's which would cause it to show misfire on 3&4.. now in your case it might be something.. I had it show for me while driving on the highway and flashing with no loss of power.. It's been like 5 weeks since it's come on\ have you checked the plug wires and spark plugs? have you tried misting down over the engine at night to see if you see any arching? Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted June 20, 2011 Author Share Posted June 20, 2011 Hah I recall reading someplace that one of the model years for the outback had funky acting ECU's which would cause it to show misfire on 3&4.. now in your case it might be something.. I had it show for me while driving on the highway and flashing with no loss of power.. It's been like 5 weeks since it's come on\ have you checked the plug wires and spark plugs? have you tried misting down over the engine at night to see if you see any arching? Plugs and wires are about 5 years old with about 55K miles on them. The wires still look good, I pulled wires 3 & 4 off at the coil pack to find that all looked well. I will do the water misting at night to see if I can cause arcing. I have done the misting test years back on previous cars to know that the test works well. Thanks for the reminder. Maybe all the humidity in the air caused the wires to short out. Running the car for a while, then returning 10 minutes later with a heated engine bay maybe dried them out. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted June 21, 2011 Share Posted June 21, 2011 The fact that both 3 and 4 were doing it calls into question the coil pack and the ignitor module on the firewall as well. Either could have been damp.... but with the wasted spark system the coil pack only has a single coil to drive both the #3 and #4 plugs..... thus if you have a misfire on those two cylinders it's almost a sure bet that the coil and or the ignitor is the cause of the problem. GD Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted June 21, 2011 Author Share Posted June 21, 2011 The fact that both 3 and 4 were doing it calls into question the coil pack and the ignitor module on the firewall as well. Either could have been damp.... but with the wasted spark system the coil pack only has a single coil to drive both the #3 and #4 plugs..... thus if you have a misfire on those two cylinders it's almost a sure bet that the coil and or the ignitor is the cause of the problem. GD Thanks General Disorder. I wondered about the integrity of the coil pack. High humidity and storm water entering the engine bay even when not driven can cause problems. I drove the car a round trip of 50 miles tonight with no drive ability problems, and no CEL code(s). I will remember your advise should this problem occur again. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted June 21, 2011 Share Posted June 21, 2011 Misfire codes go by cylinder. P0301 is cylinder 1, 302 is cylinder 2, 303 is cylinder 3, and so on. Misfiring after rain could mean moisture is getting into the spark plug wells or the coil pack. Pull the plug wires and look for water on the ends. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted June 21, 2011 Author Share Posted June 21, 2011 Misfire codes go by cylinder. P0301 is cylinder 1, 302 is cylinder 2, 303 is cylinder 3, and so on. Misfiring after rain could mean moisture is getting into the spark plug wells or the coil pack. Pull the plug wires and look for water on the ends. Good advise..........thanks! Quote Link to comment Share on other sites More sharing options...
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