Q: P0171 and P0170

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Bought car a drove it for 2 days. CEL came on so I pulled the codes. P0170 and P0171. Used a higher end code reader and pulled additional code, p01399. Erased those and ran injector cleaner trough gas tank. CEL lit up again about a 1 1/2 weeks later, pulled p0170 and p0171 again. Very low idle if I come to a complete stop, doesn't die though.

My car has 167419 miles.
My car has a manual transmission.

Hello and thanks for writing in. Code P0170 relates to the computer detecting a fuel trim that is outside of a specified range which could mean that it is either running excessively rich or lean depending on the circumstances. Code P0171 indicates that a lean fuel condition has been detected, which could be a result of a bad fuel pump, a clogged fuel filter, a dirty or faulty mass air flow sensor, a vacuum leak downstream of the mass air flow sensor, a faulty oxygen sensor and many others. This would help to explain the low idle when coming to a stop. I would suggest having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

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