RV Repair: Carbeator ?, chevy engine, carberator

Question
My motor mome has a 454 Chevy engine with aproximatly 50,000 miles. When driving up a slight hill the vehicle "bucked" this "bucking" accured two more times on that slight up grade then disappeared for the next 300 miles or so. As we neared home the bucking re-accured but more accute.
At this time the engine starts fine but stalls when put in gear. I changed two fuel filters, Transmission filter and tranny fluid. I have not changed the stone fuel filter that is at the carberator because as I turn the nut the fuel line is twisting.
Any help would be appreciated.....
Thanks....

Answer
You probably have a good old case of vapor lock caused by fuel being heated in the fuel line and turning to vapor and stopping the flow of fuel.
It could also be a failing fuel pump.  Just because it's getting fuel to the "carburator" does not mean it's enough to do the job.