Could be the patch failed or you may have a cracked fuel line or hose fitting that leaks when the system has an elevated pressure. Your fuel line has about 10lbs of pressure and after you turn it off will slowly loose pressure until it gets below whatever pressure is needed for the leak. Try looking for wet hoses or fittings.

Good luck.

If it's leaking while it's running, then it's not the tank, it's a fuel line. Check all the fuel lines and connections. That is where your problem is.

it could be the gas line was not property sealed when connecting it bacl to the gas tank. I would take it back to the place where you had the tank repaired. This is a very dangerous problem and should be fixed right away.

it must have a small hole in the fuel line somewhere it keeps leaking because it's under pressure for a bit.

You need to jack it up and stands and run it and watch fit leaks.

Hi there. I have a 97 Toyota corolla that is leaking gas. We thought it was a leaky tank and took the tank to be repaired. They patched a hole and we put the tank back on. It started leaking again the next time I drove it. It is leaking quite a lot but only leaked while it was running and for about 30 min after. It stopped leaking and there is still gas in it so it is not out of gas. Since it is only leaking whike running and right after could this be they didn't patch the hole in the tank correctly or could it be another problem all together. Thanks in advance for your answers!