My mate has just bought an Audi with the APU lump in it. 99% percent of the time it starts first time with no problem.
THen occassionally, when he goes to start it, it will just crank and crank. After about 15/16 attempts, it will start but sounds like its misfiring like mad, puff of dark blue/black smoke and then after about 20seconds runs on all four fine and dandy with no smoke. And will continue like this for a days/weeks, until it decides not to start.
He has changed the plugs, leads look new and doesnt have any other running issue once up n running.
Nothing is coming up when i scan with VCDS (Although not tried it whilst the car struggles to start the car)
Is this something common? Anyone else had a same/similar issue?
Car always starts in the end, just takes alot of time sometimes before it does!