Thats no Moon, Thats a space station!
When you got the engine replaced did you get a new throttle body or use the old one?? as i had a similar issue that went on for ages till i got a new throttle body then all was good.
Audi S3 8L BAM 225 2002 - Ming Blue : Silver Heated Leather, Armrest, RNS-E - Bose, Alloy Mirrors, 18" RSTT`s, Sunroof, Cruise, AutoDim Mirror & Usual S3 Extras.
Mods : Badger 5 Stg 2 Custom Map, FMIC, 3" DP & 200 Cell Cat, 007P, Jetex Filter & 80mm TIP & Heatshield, Complete LED Kit, Gen VW Aero Wipers, Full Powerflex Kit, R32 RARB, AP Shocks & Springs, 15mm Front & 20mm Rear Spacers, BB Uprated Actuator, N249 Delete & Catch Can, AP TVR 4Pot Brakes & DS2500`s, Sachs Carbon/Kevlar Clutch