Our 00 2.7 tt is in trouble.

It smokes badly, (sucks oil big time ) runs rough. It put out a cloud of smoke , was shut down and towed home. The coolant is clean and full, no abnormal engine lights.
Question is , Where do I start to troubleshoot the problem since I can't find a info or book (Bentley etc) to use as a guide???
We just had a water pump replaced (with timing belt) and they left a "few" hose connections loose. They were tightened and car ran well for a month. No other problems before or since the dealer pump job.
Your help and comments are welcomed....