my dads 1999 45k mls C240 with 2,6l 112912 engine has recently developed a strange problem. when you hit the accelerator hard the check engine light comes on and the engine loses power like it is not running on all cylinders. this stumbling goes away when we stop and restart the engine(however the check engine light stays on). our indie took it to MB to read codes and and it threw every code from plugs to coils, O2 sensors right side, brakeassistant and so on.....so MB wants to start with coils, but the engine is running fine as long as you don't push gas too hard... what about cat? only cylinders 1 3 5 have problem. anybody out there had a similar problem? where should we start????
cheers,
reinhard

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E 240 2000
E 320 Coupe

Most common problem is a VERY lean mixture under load, fuel presure problem(filter) or defective air mass sensor returning incorrect voltage signal!

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Thank you MB DOC.Will check fuel filter and swap AMM with known good one from my recently aquired E240. My 320 Coupe died in the last snow a neighbour slid into it with his SUV. Will post outcome...
Thank you,
reinhard

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E 240 2000
E 320 Coupe

swapped AMM with no result. how would i check fuel filter and where is it located??? any other suggestions? could it be one of the cats?
thank you,
reinhard

__________________
E 240 2000
E 320 Coupe

may want to try the forum at

I have a question, when you hit the gas and the engine balks what happens to the tachometer? rpm needle falls to zero immediately or the needle stumbles downward?

when were your spark plugs changed? and the wires - have you checked them with a volt/ohm-meter for resistance.

Is your car running the original battery?

After you swapped AMM did you disconnect the battery in an attempt to clear codes/CEL light?

Also check for a vacuum leak around the intake; throttle body, manifold.

Fuel injection - you need a manual to diagnose that, but I would do new spark plugs and wires, and if that didn't work would check the fuel injection starting at the fuel filter.

nothing happens with the tach it just showe the speed, plugs changed 10000mls ago, i did not diconnect the battery and it is OEM mercedes.
i have not measured plugs and wires yet. what should be the resistence??
thank you,
reinhard

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E 240 2000
E 320 Coupe