STALL UNDER ACCELERATION (WTF?!)

Sep 13, 2014 | 11:02 PM

MALOSINZ

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Junior Member

Joined: Nov 2013

Posts: 31

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Silver C55 AMG Sedan

STALL UNDER ACCELERATION (WTF?!)

Hi guys,

Apologies for the swearing in the title. I have searched but nothing satisfactorily answers my issue(s).

In the past couple of months (2004 C55 AMG sedan - 60,000-miles) my car has:

Rough start
Rough idle
Nearly stalled a couple of times (at low speed)
Actually stalled once (luckily I'd pulled over prior to - and stalled right in the way of an angry cyclist...bl***y cyclists...let's not get into that rant though)
Shocking fuel consumption (as low as 4.6kms/litre...rough guesstimate of 10.8mpg)
Slightly blackened exhaust (I guessed from running 'rich' as in too much fuel in the air-fuel mixture - I'm no mechanic but I understand this concept)
At 2/3rd acceleration in 'D' (often when uphill) the vehicle 'stalls' for the lack of the a better word. It doesn't actually stop but it interrupts the acceleration. Makes me hesitant to 'get on the gas' whenever the urge takes me (which, let's be honest - is why we all drive AMG's right?!)

In the past four weeks, I have had the following done to my car:

Fuel Pump replaced (failed on me one Sunday morning)
MAF replaced
All 16 spark plugs replaced
Dyno tuned out the 'rear oxygen' sensors (took out rear cats)
Attempted to re-flash the ECU (did not like it - went into 'shutdown' a couple of times)

The car is running well now EXCEPT for the weird acceleration-stall thing. It's Sunday afternoon at the moment here in Auckland so no shops (i.e. approved AMG mechanics) are open.

Tomorrow I intend to stop by the nearest one ask to check the following:

Fuel injector pressure (can they do that without taking them out?)
Fuel pump (if it's inside the tank...can they do that without emptying the tank and rummaging around inside it?)
oil filter
oil quality

I'll get them however to do the following:

Full oil change (I should probably do it myself - there must be a C55 DIY oil change somewhere on here right? Car Jack/Ramp(s) - Drain nut on sump - drain out - guessing 9-litres of 10w-40 (MOTUL?) and replace the filter while I'm at it
Price on a) injector clean and b) injector replacement

I know this is a long post but it is important (to me at least :-) ) so if anyone has a) experienced this and ID'd the problem or b) knows more about fuel systems / reasons for acceleration stall than I do - PLEASE CHIME IN!

Cheers,
MALOSINZ