Have solved computer read out problem. Met up with an ex-audi technician who suggested disconnecting the battery for 15 minutes. When i reconnected, the system re-set itself. Very pleased about that as i did not fancy the possible costs involved in fixing or replacing the on-board computer. Still have a problem with fuel, black smoke still pouring out exhaust when car under laod or revved up whilst standing still. Any suggestions as to what could be causing this.