2004 Subaru Forester Q&A

2004 Subaru Forester Question: just failed Mass Emissions Inspection. OBD codes P0303 and P0457.

What do these codes mean and are they expensive to fix? Car runs fine and I am used to the CEL on (especially when it's wet out)But it had always gone off before this year. 130k miles. -
Answer 1
p0303 cylinder 3 misfire p0457 evap. system leak detected. Usually not too expensive. Cylinder 3 probably has bad spark plug or ignition coil. Evap. system leak can be found by a shop running a 'smoke test' to locate the leak and then repaired. -
Comment 1
Thanks so much! Could the p0457 be from the gas cap? If the p0303 is coil how much would that cost apprx? Are these dealership services or local mechanic? -
Comment 2
Local mechanic can perform these repairs. About $100 dollars for coil plus labor. Evap. system depends on what they discover the problem to be on 'smoke test'. It can be just the gas cap has a failed seal and replacing could take care of it. -
Comment 3
Thank You again! I am really glad to hear it's not something big and expensive. So glad I found this site and your valuable knowledge and experience. -