good idle then bad idle...then good
Just a note...
When I replaced the plugs and the voltage regulator on the 560 sel, the vehicle began to run well for a short while and then after a few days the idle problem came back. I looked under the hood and noticed that there was a blue halo around each of the plug wire connectors. BAD WIRES! I relplaced them. Now the rough idle was constant, up and down the rpm scale. This led me to believe that there was some other problem such as a bad injector or perhaps the ignition coil, etc. I spoke to my mechanic friend and he asked me if I had checked the plugs again, because one was probably fouled. The number eight plug was fouled, I replaced it, and the car runs like a dream.
It would appear that these cars, with oil burning through the valve guides, need to have constant attention to the plugs. I know that this was not the solution to other posts here, but I did also have to put in the plug wires and the voltage regulator...