Similiar issue. While coming out of the store my ML500 started up like a loud truck with rough idle. Plugged it up and got CEL codes P0131 and P0456. I can also smell exhaust fumes, gets louder during exceleration. We changed the O2 sensor to a bosch on "passenger side" code P0456 code went away but still getting P0131, loud/rough idle and exhaust fumes?? Can this be a leak in the exhaust? Cat converter need to be changed? Vacuum Leak? Or fuel filter? This is a major headache! HELP!
My car has 160 miles.
My car has an automatic transmission.
Hello. Codes P0456 and P0131 can come up from a serious exhaust leak. From what you are explaining, it sounds like this is the issue. The exhaust leak will need to be located and repaired before further testing. If there is no exhaust leak, then there may be a leak in the EVAP system from one of the hoses or in the top seal of the fuel tank. If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose the fumes and rough idle.
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