C240 2001 Miss Fire

[dwlincoln]

Had the car serviced 5 weeks ago since then it has been missfiring on idle
EG when slowing down or comming to a junction it nearly stalls,

Took it to a merc dealer who says it will need a s---t load of money spending on it because they are sugesting it is the 02 sensors 7hrs labour!.

has any body any advise on this please i have had no fault lights! at all.

also were on the engine is the 02 sensors!?!?!? Thanks.

 

[colechelle]

Two before the CATS two after, normal fault on that engine is air mass meter, poss coil leads, (2 per coil)

 

[dwlincoln]

were is the maf and what is the best way to clean it, excuse the ignorance
i just drive the car i dont have a clue about the big bit in the front.

brother owns an alfa v6 and is a regular at cleaning the maf ect ect ect.

thanks!

 

[colechelle]

as you look at the engine to the left your see a pipe from the air box with a 6inch tube and a 5 pin plug going to it, clips one end jubiee other thats the maf, clean with carb clearner, i belive there a DIY secton on here for cleaning them

 

[dwlincoln]

Will have a look thanks!!!

 

[colechelle]

Just looked, the car on the section looks like a c220 but its all the same method!!!

 

[jberks]

No Its Not The Mas

Well probably not anyway.

I've had 2 occurances of idle misfire on this engine. Both times, it was cured by a new set of plug leads. My experience is that they start to degrade after 3 years or so and this is the main symptom.

As its twin spark, the misfire isn't severe and almost inperceptable on running but at idle and auto creep its a real pain.

If they've fiddled with the plugs / leads during the service, this is the first thing I'd look at. There may be corrosion in the suppressor caps, the caps may not be fitted correctly (they are a bugger) or it's just age.
The dealers are clueless about this fault and told me mine was normal. After a lot of hassle (4 visits followed by 4 solid days in the workshop) in desparation, an indie swapped the leads asif by magic she purred again.
3 years later it started again. New set of leads and she was back to her old self.

BTW - I had the MAS and o2 sensors replaced on mine when they went (MAS killed the O2 I believe) - £500 inc Mian dealer supplied parts. £700 for an o2 sensor - pah.

Sorry - just re-read the post and not so sure - leads are normally more subtle. Near stall could be the MAS.

 

[dwlincoln]

thanks for that i will do as you sugest and change the leads see what happens