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Random misfire on highway speeds

This Audi had a hard to diagnose problem: when going on a trip driving on the highway, it would throw up random misfire codes. When trying to accelerate on the highway, it would also seem like the engine did not have enough air.

If you follow online advice, you'll be stressing over replacing the expensive coil on plug modules. Don't.

If the car has over 100k miles, and the oxygen sensors and the catalytic converter have never been replaced or cleaned, remove the oxygen sensors and look if there is a lot of soot and dark deposits. If there are, this MAY be the cause of the random misfire codes.

Note: you need to scan the engine with freeze frame data to see at what speeds the error code came on. Also do a VAG scan. Also make sure to use appropriate grade of gasoline for your car before proceeding any further.

If the oxygen sensors are black with deposits, use the information on this site to proceed.

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