Thank you for the answer. I think the dealer only change some in the mechanic adjustIt is managed by the ECU and not a VCDS-adjustable value. Have your dealer do an actual vs specified scan (on VAS) to detect any incorrect coding in your ECU ... Otherwise you may have host of external influences, cold-start air system, timing or O2 sensor issues - also MAF, inlet air filter, fuel pressure, injector pressure or sticking (bad gas, water in gas, water in oil) - gosh another 100 I could imagine ...