Misfire codes P0303 and P0304

[scoobymom]

After driving the 2003 scooby any number of miles, if I turn it off and shop for a while it misfires when restarted and codes P0303 and P0304 and code 0420 bank one efficiency codes come on. If I wait till the engine cools down 2 hrs plus it starts and runs fine. Also, if I drive it but don't shut it off it runs fine but eventually the check engine light comes on. Why would it only misfire after driving and then turn it off? VERY INTERMITTENT PROBLEM. HELP


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[dalerich]

I don't know much about your codes. I believe the engine, and engine compartment, are the hottest after you drive and park. The issues could be related to expansion from this heat that is causing poor connections to not connect at all. It may not hurt to check and clean electrical plugs with some electrical contact spray cleaner. I have not done this on a Subaru yet, so I could not tell you the critical connections to clean. Had similar issues with my dodge van, and a good cleaning of the electrical plugs seemed to fix the when hot not starting issue I had. And I had engine light related to it before the cleaning too.

[scoobymom]

MANY THANKS, WILL CHECK CONNECTIONS AND CLEAN


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