MercManiac

I've taken my car in twice because at idle (in park or D) and (AC on or off) car shakes or wiggles. Atlanta Classic say they can't find anything......but for the first 18k this engine was as smooth as a turbine!

Any ideas??

Also, don't know if it's related, I get bad vibration from 78 to 81 mph.....in my seat and the empty passenger headrest almost shakes out of the seat. Just put new tires on and still happens....had them on-car high-speed balanced to 140mph......this also happens on all road surface conditions.

Thanks in advance for your help.

awiner

Sounds like a bad MAF (Mass Air Flow Sensor) may be the culprit. Has your dealer tested the MAF ?

Also, have you tried other brands of fuel ? I had a similar rough idle problem that was very inconsistant. Only happened at idle every once in a while. I Changed brands of fuel and it went away.

mbtech208

There are too many variables that could cause a rough idle. I'm aware of a bulletin on the 137-series engine (yours) that says that the engine, when under cylinder-shutoff conditions, could draw oil into the intake manifold and foul out the spark plugs, causing a misfire. But this would generally make your Check Engine light come on. I can't help you anymore with that problem, it's something I'd have to have the car in front of me to diagnose.

MercManiac

Thanks Adam and Dave......I'll let y'all know how it turns out.

S500Sport

Might be the fuel grade. I was cheap used the 87. Use ultra.

blk350

same thing happened to my 03 S600,it was the coolant temp sensor.