1. Make sure you have no boost leaks.
2. Make sure the MAF is clean.
3. Reset the ECU by disconnecting the negative battery terminal and press the brakes a few times to ensure there is no power left in the lines. Wait like 15 seconds then reconnect the battery.
4. Start the car and let it idle to warm up.
5. Drive the car around for 5-10 miles normally.
If you have a laptop you can buy a vagcom cable and install romraider and get some logs for us. Or if you have an Access Port you can do some logging and attach the logs up to the site for us to review for you.