I'm have a 2006 BMW Z4 3.0. The engine light came on the other day and I took it to advanced to hook it up to the computer and it said cylinder 5 was malfunctioning. I replaced all the spark plugs with Denzo TT cpark plugs, but it's still running rough. I sounds like it's putting. It's hard to describe, but I need some advice on wht to do next. I'd rather not take it to BMW as all of you know its going to be expensive. Please help me out. Thx