Hello, please help i have an A3 which has given me problems since the day bought it over 3 years ago, at the moment it is showing the following codes, P0671 Cylinder glow plug, P0673, Cylinder glow plug 3, P0674 Glow plug 4, P0238 Manifoild pressure boost sensor, P1592 Altitide Signal boost sensor and finally P3102 Motor for intake manifold flap. The car now throws out black smoke on acceleration. I was told that it may be a problem with the wiring which the garage sorted and replaced some of the sensors. They said the black some was down rubbish in the pipes and would clear 500 miles later its still there, some how i don't beleive them. The car was going in to limp mode, but since the garage have tinkered with it limp mode does not kick in... Any help would be appreciated. Thanks.