Lately, I've been noticing that after my car has been idle or parked for quite sometime,
after starting it, reversing andstepping on the gas, I hear a buzzing noice that seems to
come from under the car and the carfails to accellerate. It's been on and off until today,
not only did this happen, the 3 lamps on the left dashboard (ETs/BASP, check engine
and forgot the other) came on. I stopped and restarted then the lights went away and
drove fine. I stopped by for food on the way and when I started, reversed the car, the whole thing happened again.

Has anyone experienced this before? What's causing this? I plan to bring my car to
the shop tomorrow but would like to have an idea what the problem is and how much
it would cost to have it fixed.

thanks in advance!

 

I had a similar age ML270 that had similar symptoms but didn't have any warning light came on. I took it to the dealer and they found out that the catalytic converter blocked the exhaust and need replacing. They also change the air flow meter since this caused excessive fuel injected to the engine that damaged the catalytic converter whichmade the cranking noise. It worked fine since these replacement had been carried out.

 

Your Catalitic converter didnt fail because of your mass air flow sensor. Mercedes builds crappy converters period!

I think the buzzing noise and lack of power are two different things. The buzzing noise could be a bad catalitic converter. And as far as those lights turning on and having poor acceleration could be many things. Prabably bad speed sensors in your transmission valve body..