Right, i've just bought a 96 e39 540i.
Two days after i got it the car starts to idle funny, feels like a slight mis-fire and the car vibrates. The vibrations get worse up to 2000rpm, then it seems to be fine?!?
I've cleaned MAF, ICV, put new spark plugs in - not the slightest difference.
I'm thinking it's cat related
Need help