Good evening from Nashville, Scotty! My uncle has a 1997 Mercedes E420 with an automatic transmission and about 160,000 miles on the odometer.
It's had a Check Engine light on the dashboard for a year now--specifically for the Mass Airflow Sensor--and as of this past week, after he added some oil in the engine, the car cut-off while he was driving down the highway but he's always able to turn it back on. He can also feel the car shaking a lot while it's idling and driving, and it still shakes even after he puts it in "Neutral" so I'm guessing it's not bad motor mounts that are causing the issue.
He bought it over to the mechanic today and they said it needed a tune-up; they put on new spark plugs, changed the oil, and when he drove off the car still shut off. What could be the issue? I'm also wondering if he might have added too much oil in?
Can you please tell use what codes you're getting regarding the MAF sensor?
Where you have to add a ton more oil for it to actually run bad if it's over fill check the dipstick first. Just realized he has an endless money pit Mercedes and at that age all bets are off a billion things can make them run poorly and many of them will cause more than a vehicle's Worth to repair. Sometimes it's better to say goodbye with a Mercedes that old than to put a ton of money into it. But what the heck if you don't mind bringing it to Clarksville I check them out free Monday through Friday
If the ECU throws a MAF-related code, why not just replace the MAF before anything else?
If I remember correctly, I had a MAF-related problem on my Benz at ca. 200 000 km; tried cleaning the thing, but it did not work; but a replacement did help. It is an easy job.
BTW I also figured out that it is a hard job to try diagnose a MAF yourself: its output signal has very tight tolerances. So if your ECU says your MAF is ot OK, it probably is not OK and worth replacing.
P.S. Why would someone want to continue driving around for a year with his CheckEngine light on, potentially ruining his expensive car, instead of fixing the issue asap? (rhetorical question)
