I helped a guy who got a "good deal" on a TT that he bought from a guy who "owned a shop". It was lightly modified (exhaust, intake, strut bars, etc) and the only problem it had was a miss in the drivers side bank. Went over there and verified it was 2 or 3 connectors. All of which were on the same bank. Didnt really think anything of it. We started it up, and it was still low on power. Several days later a bunch of us helped him out and checked his injectors...a bunch of them were bad. Replaced them and he started blowing TONS of smoke through the drivers side exhaust. My suspicions tell me it was intentionally set up to miss on that bank for the sale of the car because the guy was aware of the issue.