Hi all, just bought a 2009 hyundai tucson city sx last week. Took straight to the mechanic as fuel gauge seemed to be dropping down quite quickly. They found the issue and they replaced the main fuel gauge sender unit and sent me on my way. Straight away after I picked it up from them I went to the fuel station to fill it up. Fuel gauge needle was sitting about 2mm under the 'full' level. I called the mechanic and he advised that it was most likely not filled on flat ground. I understand that it might not have been the flattest ground at the service station, but I also doubt it would be on that much of a slope that the fuel gauge would not read as full. Could anyone please give me advice what could be causing this??