Problem: the car runs rich, and can't pass emissions test. Engine runs ok on petrol, but runs a little bit rough on cng. Still, the same condition both fuels. There is no check engine light or dtc's stored. Checked with vcds and odis. Things that I have done. 1. New sparkplugs and ignition coils, checked the wiring also --> ok 2. Vay Tiền Cấp Tốc Online Cmnd.

passat 1.4 tsi ecofuel problem