I've noticed that my car seems to shudder a bit at low rpm in 1st. I noticed today that, when I revved it to about 1,600 rpm it ran fairly rough....almost like a cylinder was missing. Now, the car's definitely not down on power (not long ago ran the 1/4 in 14.1 @ 100 mph on a hot day), and it idles perfectly. It also runs thru the rpms real smooth, with the exception of that one rough spot.

Is this typical, or is the car indeed not running right? Could it be the fuel injectors (car has 53k mi)? Faulty plug wire?

Any advice appreciated.



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Best regards, Michael
'92 500E
'88 300TE

Have the engine put on an ignition scope by a Mercedes Tech. Be careful not to let them do any adjustments that are not needed. If it needs the resistor tips or the dist. caps or rotors, do them.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

You probably have one slightly plugged or bad (resistance) injector. Try a bottle of Redline injector cleaner to see if they problem goes away.

If that doesn't work, put the engine on the ignition scope to identify which plug/injector/wire is bad and replace as needed.

I have also heard, but cannot substantiate, that 500E motor mounts can fail a la Porsche 944 mounts. That would also account for a feeling of roughness, at idle and slightly off idle.

I'm gonna have an ignition scope thrown on it for good measure, and have the motor mounts looked at by a Senior Tech I hooked up with who does work on the side. Will post the resolution.

Thanks for the input gentlemen!

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Best regards, Michael
'92 500E
'88 300TE