Q: Car won't pass smog.

asked by on February 19, 2016

My car will not pass smog. The codes that appear are for random misfires, a higher than normal idle, and bank 1 being too lean.

Engine idle speed is high Inspection $79.99 - $89.99 Get a Quote

Hello! I will be happy to assist you. On your particular vehicle, random misfires are commonly caused by things such as low fuel pressure, a faulty oxygen sensor, bad vacuum lines, or faulty air flow sensors; a broken or loose vacuum line would be the most common of these for a turbo vehicle, such as your Jetta, since turbo vehicles use a lot more vacuum lines than those with normal engines. I suggest having a certified technician, such as one from YourMechanic, inspect your vehicle for the cause of the high idle condition, and possibly use a smoke machine to test the vacuum lines.

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