Guy I need Help Please, I have a 1999 SL 500 129. It has 66,000 miles on it I wanted to sell it and decided to change the Spark Plugs. After I did the left side I took it out for a Test Drive.
It ran great. The next day I replaced the remaining Right side total of 16. I took it out for a drive and It began to stall and Idle Rough on me. I checked all the plugs for gap and they came out
okay. I did not mess with anything else on the Engine. I did replace one Coil that was showing Bad. Other then that did not do anything to the engine.

Can you Help....
Thanks in advance,
Sergio