just replaced plugs,coils and plug wires on 2000,c230komp. found lots of carbon on plugs. i have been getting rough idle and shakeing at morning start up. smooths out but does not go away after driving awhile. starter has been making laboring noise also. have a new battery. motor mounts are good . o2 sensors are original. 90,000 miles. MAS replaced about 20,000miles ago.no check engine light warnings. ran ok for a day after tune up. then back to roughness. ECM a possibility and where is it on this car? Thanks

test your coil readings and the wire for resistance reading, not all new parts are perfect. also if there are too much carbon on the plugs, try adjusting your CO, that might mean too rich mixture.

Did you change the plug connector/resistors under each coil???

no i didn't change the coil plug resistor extensions. i'll try that tomorrow. i also put in platinum 2 plugs. the book say's the application's fine but i'm reading that they could cause ignition problems. is that with 2000 230 also? thanks for the response. it's also been suggested that my ECM is bad. does this seem possible? car ran well yesterday but temps were above 40. this morning the vibration was back and temps were well below freezing. wondering if MAS is bad again. 20,000 miles is a pretty short life span for a $430 part. dealer ripped me good also charged $340 to install. cleaned air filter pasages and put in new filter. joe d

before you continue to throw $ out the door, i suggest you do the proper diagnostic steps. Changing everything in the electrical system may be good if you don't mind spending but if your goal is to save then save and follow proper protocol.

hello cool,
I am getting on my car (260E, 1988, Euro, headgasket changed 10 months ago) for the first time after 19 years and 440000km carbon on the plugs,

Do I understand correctly the test protocol, first
reading 1Kohm on each plug wires, then adjust CO.

Thanks

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Keep us posted especially if your problem is solved
Present cars:
My car: E-class 420CDI, 2008, W211, V8, 180 000km

Wife's one: C-class 220CDI Sport Coupé, Euro, 2002, W203. 345 000km

Son's one: GLK class, 220CDI, 2009, W204

Sold: E-class 260E, 1988, W124, Wonderfull car sold after 489 000 kilometres of reliable services (engine M103, clutch, brake system and 5 speed manual gear box all original).

Sold: E-class, 320CDI, W210, 2000, 225 000km

checked wires and their ok. temp above 40 today and car ran fine after about ten minutes of driving. start up was still loaded with vibration when car put in drive. taken out of gear- idles fine, no shake. after heat up runs good. where is CO adjustment on 2000 230k? Same symptoms as before MAS was replaced about a year ago at dealer. could it (mas) be defective again? thanks for reply,s

sorry posted before reading message. will go to other board. thanks for your help.