low lambda

Anyone come across this before? 1998 CLK200 Auto with 68,000 on the clock has just failed its MOT on emissions. CO and HC are way high and Lambda is low. Chap doing the MOT said it needed a new cat but I'm struggling to see why the cat would cause low lambda. I've pulled the plugs and...

hi guys i am new to this so please excuse me if i mess up. i have a problem with my 2003 mercedes w211 e200 1.8 kompressor. it failed its nct test showing high co (aprox 3.50) and low lambda (aprox 90) meaning rich mixture. i borrowed a friends same year and model car with good emission...