Not a truck but there should be no matter on the issue.
1941 Ford coupe. Flathead v8. Performance intake, dual carb. The issue is the throttle sticks for the little bit then busts free and moves like normal beyond that point.to return to idle you must pull the pedal that last bit. this only happens when it's running. It's not in the linkage because I have disconnected it and can feel it's carburetor. This issue has only showed up after having the carburetors rebuilt.But we switched from the Weber back to the Ford carburetors and the problem is still there. The webers have been on there for over 12 years.

 

Have you checked for any linkage that might be catching?
If they were just rebuilt, you need to double check the work. Usually you don't have the butterflys off the shaft unless they were re-bushing the shaft. It sounds like maybe they didn't get the butterflys in quite right. Or maybe even one in upside down, they have a bevel and if you get one flipped they will stick. Do both carbs have idle adjustment? If they do, the idle speed screws should be unseating the butterflys from the stuck shut position.