My 1995 Mercedes S320 failed the emission test on HC(ppm) at idle. The limit is 220 and my car is 396. I passed at cruising but failed at idling. Can you help what cause this.
I am afraid the dealer will rip me off by saying eveything is wrong. They are hungry for business now.
Thank you for you help.

Could be a number of causes.
Dirty air filter
In need of oil change
Engine not up to temperature-most likely
Inept inspection station