ML320 acceleration problem - HHHEEELLLP!

[ghmd]

ML320 Petrol Automatic - I have been experiencing problems with acceleration. When I set off on cold mornings I have to stop several times and switch off the engine. If I don't, the car will not reach more than 30 mph and sometimes even slows down. If I switch off and count to 10 it will sometimes then start and accelerate OK. I sometimes hear a sound like air in a central heating system when I turn the engine off.

Also it sometimes starts to slow down when i step on the gas too quickly. When overtaking it dangerously accelerates to begin with then slows right down in front of the vehicle I'm over taking which not only makes then really cross but is dangerous!

If I switch on the engine to warm up and the engine sound drops down before I start off it is sometimes better.

My local garage isn't very good at diagnostics so please help!!!

 

[Cole@MBS]

At a guess i would say the air mass sensor, you need a star test done,

Where in the world are you??

Welcome to the forums

 

[ghmd]

Thanks SAM I am near Wisbech

 

[Oarsman]

Give Alex Crow, on here as Alexander Patient, a call. He's in Stowmarket Suffolk.

I can personally recommend him. He's done a couple of jobs for me in the last month at very short notice. Work has been superb on both occasions.

Oh...and take some jam doughnuts with you. He says he's on a diet, but don't let that fool you.:lol:

 

[dieselman]

You can meter the MAS with a meter. Check Pin5 WRT Gnd, it should read ~2v at idle rising to ~4.8v at full revs.

 

[123-anthonyb]

Merc Specialists in your area

Hi

I also live in the Wisbechistan area, and am taking my car to Stewart and Wisbey just to the north of Ely. Very good, not expensive, Merc specialists. 01353 665343 and ask for Aaron Wisbey. And I agree, what is happening is that the engine management system is protecting the engine. You need a Merc computer diagnosis, which Aaron can do for you. ps they also provide free loan cars.

Anthony