I was getting the same gas smell about two years ago. I ended up having to replace the lines that come from and go up over the gas tank. What a pain in the BUTT! I did not see gas under the car at first either. Then WHAMO, there it was. The salt on the roads up here in the northeast rotted out the return pipe, and the feed pipe was not far behind. You have to remove the tank to get them out. Which is a BIGGGGG project. I was able to go around the outside of the tank and make it work. I hope this is not your problem. Dave.