Audi Repair Questions? Ask a Mechanic for Answers ASAP
Thank you for using JA.
Black smoke is usually because of incomplete combustion, turbo issue, air intake fault, egr problem, it can be because of many things. I would start with a compression test to see if the valves and piston rings are good. If the engine itself is good, you can then start to look at other components.
Please don't forget to leave a 5-star rating. This helps me build my reputation. Your rating benefits the experts that use their time to respond to customers. Thank you.
At 170,000 it probably is coming to an end. A compression test of the cylinders will tell you the state of the engine. You could easily check the MAF sensor and throttle body yourself, they're both on the intake pipe. A dirty MAF sensor can cause black smoke.
Glad I could help :) Thank you for using JA.