Emissions failure!!
 

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.