454 Chevy

I fought with this SAME problem for years. Turned out that the coach had 'Settled' down lower onto the chassis causing the fuel lines atop the gas tank to get chaffed on top. This allowed air to be sucked into gas line only when I was under gas pedal load as when climbing a long gradual grade. It could also be the in-tank fuel pump.

There is another 454 problem you'll suffer, if not already. I called it the old Hot Start problem... Many times when shutting off the engine for a short time, like when getting gas, the ignition would only 'Click' but not turn over the engine. Turned out that the starter motor, fly wheel engagement gear housing would absorb all the heat from the red hot exhaust manifold and distort its body. This would freeze the plunger in place until it cooled than it restarts nicely. Only fix is to get the best aftermarket heat shield money can buy. ...Oh yeah ...one more 454 problem U'll have ... The exhaust manifolds WILL crack on a consistant basis. The only help is to install THE BEST Copper Metal manifold gaskets money can buy!!!

I had a 1985 454 in an Allegro & had severe vacuum lock issues. It took a secondary fuel pump at the fuel tank to solve the problem.

gswcgi wrote:
I had a 1985 454 in an Allegro & had severe vacuum lock issues. It took a secondary fuel pump at the fuel tank to solve the problem.

With high underhood temperatures, vapor lock is certainly a possibility.

Check the distributor if it has a hall effect transistor. I had one go bad on a 1984 motorhome. Mine caused skipping like it was out of gas.

Mine did this for 200 miles ,run good then drop speed till had to pull over, cool off ....take off did same thing . Changed 300 dollars worth of electronics on the road at each auto zone in each town I came to. Took 12 hours to get to destination at night in storm. PROBLEM WAS IN TANK FUEL PUMP.
Was a 1994 Georgie Boy Swinger with a Chevy 454 engine.
Really threw me off as being fuel pump because would run great for about 10-15 miles at a time . I changed in line fuel filter , chassis rail fuel filter, 02 sensor, ECM Module, rotor an distributor , plug wires an plugs. I even bought a computer an left it in box ,fortunately Auto Zone took it back the next day because seal was not broken.

P.S. I do my own work ,costs me money sometimes .But , would rather install new parts on my rig than pay the labor rate at RV shops. Plus when I do get done know I can trust my rig to go anywhere.

The gentleman that I bought my MH from had a similar problem. After every thing got warmed up the MH would drop speed and had no power. The snorkel on the air cleaner would soften up so much that it would collapse causing the air to be choked off. I now have an aluminum drier vent tube for a snorkel.