Plugs, what kind of plugs? Brand and model?
A friend with a 500SEL just went through the same thing. The car had hardly been used in 2 years. She failed the first time: engine wasn't very warm at the test.
She added a bottle of techron to a 1/2 tank fuel, changed plugs to what was oem recommeded, drove the car hard for several minutes and got the engine hot, went back and passed.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)