2008 Volkswagen Passat Komfort 8.3L - Engine
During first 30 minutes of drive, it consumes gas crazy, and afterward, the consumption rate goes back to normal
I had this problem from a month ago, and when I first experienced this, I went to get wheel alignment, wheel balance, change ignition plug, fuel gauge sensor, fuel measure-related things checked. - None of these solved the problem. There is no check engine light on, or any other check signs on the dashboard.
Then when I paid close attention to the problem, I noticed the pattern - the first 30 minutes of driving, no matter it is constant 30 minutes, or split several occasion add up to about 30minutes, the fuel gauge drops significantly. Later, it goes back to normal.
What can be the possible reason for this? Thanks in advance!