Hi, my BWM is 13 years old. I had TÜV 2 years ago, so I was told that it did not come first because of carbon monoxide or carbon dioxide values. Then allegedly the spark plugs were changed and he got AU. He already had blue smoke in the exhaust gas 2 years ago when giving it out of idle. Now again TÜV is on the line, and I wonder how best to get through TÜV/AU. Best, without putting in a lot of money. Can I just (same) try it at the TÜV, and after the emergency after or better go back to the workshop from 2 years ago? Thank you for every info Dear greetings SL