im aus, here. Anyway i have a 05 Astra G Classic. Z18XE engine
I noticed that it has start to knock (for a second or so) when accelerating, especially up a hill, or slight incline. I use 98 or 96 Ron fuel.
Car has only 25,000 km. oil has been changed every 5000km. nothing has been modified on the car except the rear muffler.
The ECU hasnt registered any faults.
I thought id ask if you guys have any ideas.?