itsfast

Ive been debating changing out the plugs but only have 62,xxx miles on them and the beast is still running strong. Do you guys think it would be a good idea to replace them due to time and not mileage? By not changing them yet could I be at a slight loss of horsepower and just not noticing it?

Alps

id change them just to ensure they do not get jammed in the block!

AWOL

I changed mine around the 100k mark. There wasnt any issues to do it, and accordingly, i didnt notice any performance gain. I kept them for backups however.

abiazis

Check manual to see if there is a recommended time interval change........my manual for my SL65 states to change plugs after 5 years regardless of mileage........don't know if E class also states this...

skratch77

Its 5 years also for the e55 or every 3k miles if you have a tune.

Edit- every 30k miles tuned!!!

Hammer Down

Oops I still have my factory plugs in 8yrs & 20,200 mies but I do have one step colder plugs in the on deck circle