In the late summer heat, my '59 Galaxie has sometimes acted up at traffic lights. As long as I am cruising, or usually even rolling, it does great. The most common form this problem has taken will involve driving for about an hour non-stop with no problems of any kind, and then the first traffic light I come to and have to sit at it will either stall at the light after a while (idle quality breaks down first) or else it will stumble or stall when the light turns green. Sometimes it is hard to start it when it stalls, but usually I can start it back up quickly.
I haven't had issues for a while but today when I came off the highway exit ramp and accelerated into traffic it was acting like there wasn't enough fuel in the bowl--stumbling if I gave it anything more than light throttle.
Once it starts misbehaving, it will not fail to stall out if you let it idle long enough, even with the hood open and air cleaner off idling in park. I have done this a few times, even taken the air horn off and watched the fuel coming into the bowl.
Now, I am inclined to think I am dealing with partial vapor lock for two reasons: 1. idling with the air horn off, it is audibly clear that there is about as much vapor as liquid gas coming out of the fuel inlet needle. 2. Looking in the glass filter bowl on the fuel pump, you can see bubbles at the top, large and small, and quite active.
I am not certain that's the problem, though, because at the time the engine dies while idling with air horn off, there is still plenty of fuel in the bowl; indeed, it is within a 32nd or so of the spec'd fuel level.
Any ideas?
1954 Crestline Victoria 312 4-bbl, 3-speed overdrive