gas not getting to carb, sputters and dies while driving

[Hotrodlincoln]

when i added my extra tank.

Are you using the Ford tank switching solenoid? Those are known for causing this type of trouble.

Also the only reason you would get a "vapor lock" is if the Evap hose on the top of the tank has been blocked off (which is entirely possible if you have removed the tank at some point recently).
The Evap system is there for two reason, one is to catch fuel vapor rather than letting it vent to the atmosphere, the other is to provide a way for air to get INTO the tank as it drains in order to prevent a vapor lock situation. If you have removed the Evap system (lots of people do), a simple vent hose (similar to what a transmission or rear axle has) with a filter on the end of it will allow air into the tank and fuel vapors out to relieve tank pressure.

 

[strvger]

no, using a manual switch from a boat.
finally tracked it to the fuel sender i think. hoses checked out ok. pia is that the tank has to be dropped. too much stuff in the bed plus the topper to just raise it up. thinking i'm glad i did the body lift and that looks like it will make it easier. with all the crappy weather here, most likely won't get to it til next week or even the weekend.

 

[strvger]

ok, guess it was the in tank filter. couldn't find a replacement, so just cut it off and put an inline filter near the tank switch. think it should be fine now. thanks for everyone's input and help.