Check Engine Light and Engine Misfire on Mercedes-Benz R500

Failed spark plug wires and/or ignition coils can cause intermittent misfires (rough running); the Check Engine Light may also illuminate. Diagnoses of the ignition system will be necessary to determine which components are at fault.

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Average mileage: 115,085 (102,800–124,000)
2 model years affected: 2006, 2007
5 people reported this problem
3 people shared problem details
Engine running rough, diagnosed at autozone, codes were for cylinder misfires. Still need to find shop to repair and cause.
it usually occurs as you decelerate at a stop sign or light. The car will jerk, engine lights come on, it will accelerate forward then stop. Pretty scary experience. Still needs to be fixed.
Check engine light accompanied by rough engine, especially at idle. Symptoms seem to correlate with low fuel. As fuel level goes below 1/2 tank, the likelihood of the symptoms returning increase with the symptoms alway returning when fuel level goes below 1/4 tank. When fuel tank is refilled to full, symptoms always disappear. Replaced #7 fuel injector which eliminated the rough engine but did not eliminate the check engine light, which continues to illuminate as fuel is used. Mercedes technicians suspect either one of two fuel pumps or the logic that shifts between the two may be an issue. More troubleshooting required...

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