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Ron Z.
Ron Z., - Honda Tech -
Category: Honda
Satisfied Customers: 18972
Experience:  18+yrs experience. State Inspector and Honda Diagnostics
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Honda: 1999 obd code p0301 and p0135 it..runs rough..smooths..nuetral

Resolved Question:

honda passport 1999 obd code p0301 and p0135 it runs rough in drive smooths out in nuetral
Submitted: 8 years ago.
Category: Honda
Expert:  Ron Z. replied 8 years ago.

Ok. The P0301 is a misfire on cylinder #1. The P0135 is a code for an oxygen sensor. More than likely, the misfire on #1 cylinder is making the oxygen sensor set a code due to the unburnt fuel from cylinder 1 getting into the oxygen sensor and messing it up. I do believe that if you cure the misfire the oxygen sensor will clear itself out, and go back to normal. The misfire (P0301) is more than likely going to be a bad ignition coil. It is located on the passenger side, first coil closest to the front of the vehicle. You will also want to check the plug on this cylinder as well.


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