Best Upgrades for your VW MK4 GTI 1.8T – ECS Tuning
Golf 4 1.8T - 464hp - CarsX
Mk4 Golf 1.8T 2004, has an issue with a consistent check engine light probably having to deal with this. These tubes coming from the fuel injection system I believe had been open.
Volkswagen Golf IV GTI 1.8T | Gran Turismo Wiki | Fandom