I have a 1988 300E (Gasoline). It runs like a dream however, I recently went through emissions (Colorado) and failed both the HC and the CO. The readings were as follows:
HC = 3.8756 (limit = 2.0000) CO = 63.6603 (limit = 20.0000)
Can anyone advise me on what may cause this and how I may (cheaply) fix this problem before retesting - I need to get the vehicle registered SOON and can't afford a major repair!!!

Sounds like the fuel mixture is out of adjustment. OR the O2 sensor has failed.

You need to have the DUTY cycle read & adjusted.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator