351w acting like a woman

made it out apr.10 miles off fort laud. then back, had plenty of fuel. started acting like it was out of gas - never stopped runing, it would stall if i gave it gas. ran like this for apr.2 miles, them like a switch was turn on real smooth @ 4000 rpms for apr 2 miles then died again. changed the coil, whet out did good for a while, now back to the same this. guess it was't the coil, any ideas ?

I had a strange one in a jet boat last year that someone else solved for me. Problem was condensation in the distributor. Boat ran great for 15-20 minutes, then sputtered below 2000 rpms though it would still run at higher speeds. Turns out the water sits in the bottom of the distributor until it warms up, then vaporizes and causes mis-fires. Stop the engine and it condenses again. Fix is to open up the distributor and either let it air out for a day or more or use a hair dryer to try to dry it out, I did both and problem solved. Not sure this applies but thought I'd mention it.

87, FN, 351 w 250 hours standard stuff. we baught new W from factory in 2000

Waterdog is moving in the right direction with the vent, if it seems like a fuel problem it probably is, if the gas cap trick doesnt work check any fuel filters condition of the lines etc. Possible to have some crud floating around your float bowls causeing this type of problem as well, in which case a rebuild would be in order. I have seen friends replace entire ignition systems in the past to fix a gummed up carb that could be rebuilt for 15 bucks in parts...
-Joe.