I just noticed today that after filling my accord up full and the gauge went to the top, about 10 minutes later the gauge read only 3/4 full. I thought maybe I had a serious gas leak or something because it kept on going down. Then after I shut the car off and let it sit for a while, I took it for a drive and magically the gauge went back up to full! What the hell is going on? Should I be worried and take it to be fixed? Keep in mind this all happened this morning.