Thanks for all the help. Just replaced all the plugs on the passengers side. Everythings back together and works fine.

The gap on the plugs I took out is 1.5mm. The gap on the ones I put is is 1mm. My vehicle has 79,347 miles on it.

I bought my plugs from a Mercedes dealer. The box they came in said the gap is 1mm. and indicate they should be torque to 25nm; I did 28nm.