Q: 2006 Pontiac GTO - Trouble codes P0300 and P0496. Feels like misfire and/or out of fuel

asked by on April 24, 2017

Initially I saw a trouble code of P0496 with no noticeable symptoms then it went away. A week later it started acting like it was running out of gas and sounds like a random misfire. After a couple of days of that I now have both P0496 and P0300. What should I tackle first?

My car has 102500 miles.
My car has a manual transmission.

Hi There, Code P0496 relates to the EVAP system, specifically indicating that the system has detected more flow than normal during a non-purge condition. This means that the system may be trying to purge excess pressure or fumes form the fuel tank when it is not necessary to do so. This is typically a sign of a faulty vent valve solenoid or sticking purge valve. As a result, this can inadvertently cause the motor to run rich at times, although it may not be noticeable. This can cause the misfire code of P0300 to also be triggered, causing a running out of gas like symptom as you have described. Although the motor may be running rich, it may cause a running out of fuel like reaction due to the fact that the motor is unable to efficiently burn the fuel being supplied to it. I would suggest checking the vent valve and solenoid to be sure this is operating correctly as this is likely the cause of the codes you have provided.

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