Thanks. It seems as though the screen was the problem. It was completely coated.

One other thing to check s the "last chance screen"......on he LP vapor inlet tube at the throttle body.take the line off and then the two screws that hold the tube to the TB....under the tube is a SMALL screen held in place by a clip...see if this screen s plugged with debris and junk.........

On top of the Vaporizor is a 17 MM hex,take this out and finger tighten a 1/8 NPT barbed nipple to hook a vacuum/PSI gauge into and check your fuel pressure at idle AND at full RPM then pull the tilt back and let it deadhead and see if the PSI drops real low....

Sounds like a fuel/fuel delivery issue either the fuel PSI is low coming out of the Vaporizor(should be about 4.5 PSI) and it is starving for fuel or the injector is acting up and needs replaced....might also be the fuel PSI sensor next to the injector.....another possibility is the Lockoff...it has a small screen filter in it,possible that is getting plugged,or the Lockoff itself is acting up and shutting the fuel on and off,never run into that tho on this truck..