Well, drove the truck today..50 or so milrs..parked it and went to start about an hour later..starter jus cranked really fast...after reading it could be air in tank, i just unscrewd cap, screwed back on and fired right up like normal..after getting home, same thing..took cap off and started up..any ideas,.is it the cap. Its the original cap i assume..very large compared to a regualar cap