[Snakebit]

I had a problem of fuel leaking out the throttle shafts on to the intake manifold. I would run the car and the next day smell gas fumes in the garage. When I opened the hood, there was a puddle of gas on the intake manifold. I thought it was a stuck needle valve, so I removed the covers and cleaned them. The problem re-occured so when I loosened one of the fuel line block conector bolts, gas sprayed out. But the car was not running, so where was the pressure comming from? I opened the gas cap and there was a hiss of air escaping. I opened the fuel line again and no more pressure. So pressure was building up in the gas tank, going back through the return line, and forcing gas out the needle valves.

Vented gas caps only vent in, not out. I drilled a 1/16 hole in the vent of the gas cap and my problem is solved.