2006 a4 cabriolet 1.8t issues...
 

OK so I'm new to this forum I recently purchased a 1.8t a4 cabriolet 2006. When purchased it displayet codesign for multiple cylinder misfire and cylinder one misfire. The car idles fin and revs fine. I did compression check last night and all cylinders are around 110psi. The snark plugs smelt like stale gas it had an 1/8th tan so I filled it with premium. The spark plugs had a white sediment on them like toasty white. I'd what that means. I thought that means it is running lean but I'd like some of your guys input. Confuses that the entire engine would be running lean. I replaced all plugs with the recumended bosch platinums. The car revs good while sitting still but when accelerating it is rough around 2k-3k rpms. Also when I start the car it sounds real deep then quite up. Then sometimes makes the deep sound again. The turbo also sounds like it stops spinning within 30 seconds of shutting off the car. The car currently has 172k miles on. Please tell me anything I should try. I have 15 years experience working with cars. I own my own auto mechanics business where I do mobile services at people's jobs and roadside. I just have no knowledge of these vw and audio turbo engines. I mainly service bmws 70% of the time. Lol