NHTSA Complaint #10137160 — 2000 MERCEDES BENZ ML320

MY 2000 ML320 WITH 53000 MILES HAD SUDDENLY SHOWED CHECK ENGINE LIGHT WHILE I WAS DRIVING IT ON THE HIGHWAY AT ~65 MPH. I EXIT AND AS I SLOWED I COULD SENSE THE ENGINE WAS RUNNING VERY ROUGH WITH SHAKE AND STRONG VIBRATION. THEN AS I STOPPED THE CAR AT THE RED LIGHT AT THE EXIT, THE CAR IDLED VERY ROUGH AND LOTS OF VIBRATION AND THEN THE ENGINE STALLED (AND SHUT OFF). I IMMEDIATELY TURNED THE KEY TO THE OFF POSITION AND TURNED THE KEY BACK ON AND THE CAR RE-STARTED NO PROBLEMS. THE ENGINE IDLE NOW ONLY FEELS SLIGHTLY ROUGH BUT IDLE SOUND IS NOTICEABLY SLIGHTLY LOUDER THAN BEFORE. I TOOK THE CAR TO THE MERCEDES BENZ DEALER (SAN DIEGO) THAT SAME DAY AND DESCRIBED TO THEM EXACTLY WHAT OCCURRED. THE NEXT DAY THEY DIAGNOSED IT AS SPARK PLUG FAILURE AND SPARK PLUG WIRE FAILURE OF CYLINDER #2 AND POSSIBLY #4. THEY RECOMMEND REPLACING ALL 12 SPARK PLUGS AND THEIR MODULE AND WIRES. AFTER THEY DID THE RECOMMENDED REPAIRS, MY ML320 SEEMS TO RUN LIKE NORMAL BUT I STILL HEAR THE ENGINE IDLE DIFFERENT THAN BEFORE AND ENGINE REV SOUND SLIGHTLY LOUDER THAN BEFORE THIS INCIDENT. THEY SAID THAT THE SOUND IS NORMAL. I GUESS I HAVE NO WAY TO PROVE THIS BEFORE AND AFTER SOUND DIFFERENCE SO I JUST HAVE TO WAIT AND SEE WHAT ELSE FAILS. THE TOTAL REPAIR COST WAS APPROX. $1280; WHICH INCLUDED 6 HOURS OF LABOR AT $120/HOUR. I TOLD THEM I THOUGHT 6 HOURS OF LABOR TO REPLACE 12 SPARK PLUGS AND WIRES WAS VERY INEFFICIENT AND COSTLY TO ME OR ANY CUSTOMER. THEY JUST SAID IT TAKES A LOT OF EFFORT AND TEDIOUS WORK TO DO SPARK PLUG CHANGES. WELL I AM NOT A MECHANIC TO WHATEVER THEY SAID I GUESS IS RIGHT. I JUST HOPE THEY FIXED THE RIGHT PROBLEM FOR THE ISSUE I HAD THAT'S ALL. *NM