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Q: I have a code P1399 random misfire

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I have a misfire , especially on cold mornings The misfire is worst it gets better when the engine warms up tho . But I'll be driving on the highway and I can feel the random misfire, that aren't so bad but I can feel them .. and it gives a code p1399 . Ive changed the spark plugs, wires , and a 02 sensor . What else do I do? Or replaces?

My car has 158984 miles.
My car has a manual transmission.

A: Hello. A random misfire can be caused by ma...

Hello. A random misfire can be caused by many different things such as dirty fuel injectors, a weak fuel pump, a bad fuel pressure regulator, fouled spark plugs or wires, a failing ignition coil or a vacuum leak. To get a more precise diagnosis, I would recommend having a certified professional, like one from YourMechanic, inspect the misfiring problem firsthand so that this can be corrected properly.

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