C320 Cat Problem???

[a6jus]

Hi
I am new to the forum, and need some help?

I have a C320 (2001 Y) Merc, that has done 133K with Full MBSH.

It has started only when hot to hesitate at take off or slow speeds?

There is also only when hot and at idle a rattle that seems to be coming from one or both of the cats?? I think the heat shield is not the cause

Can somebody give me some advice before MB fleece me out of more hard earned cash

Many Thanks

 

[Blobcat]

Hesitation could be the MAS sensor failing. The rattle could be the cat although have you had it up on ramps to check that it is not the exhaust or heat sheild?

 

[television]

The hesitation could be the CAT affecting the back presure. My CAT went the same way, just the rattle at idle or very low speeds. It always did it more in my local little High Sreet. A common cause is driving over long grass, this cools down the metal casing before the ceramic CAT has cooled, crushing it in the process.

Malcolm

 

[a6jus]

Would the cat only rattle at about 1500-1750 RPM, or could it be just the exhaust or heat shield?

I also noticed that it will not rev past 4000 RPM in park, is this normal or more problems???

Only noticed when trying to get rattle to happen.

Could the MAS sensor be easily changed by me or is it a job for merc?

Would the cat rattle if knocked while on ramps, or rattle all the time when being driven??

Regards

 

[television]

In idle your car will not rev beyond 4k due to the built in limiter, so you have no fault there.

Tapping the exhaust box from under the car shoed up the rattle, mine only did it at the same revs as yours.

Malcolm

 

[a6jus]

Have priced Cats, seem to be from £250-£500 each and I think I have two on my C320. Any benefits from the MB version except for having a lightened walllet!!
How much are the MAS sensors??? and do they come as aftermarket OE??

Regards

Justin

 

[a6jus]

Could a fuel filter give any of the symptoms as described above as this was changed about 50 K ago, well so I believe as I'm the second owner, so who knows??
This will be changed on the next trip to MB, which at this rate could be soon!!

Regards

Justin