I have A 2002 fleetwood motorhome with chevy workhorse chasis that when we go up hill it flatens out and will not go over 30 mph it kind of when you hit 75 mph when the limiter kicks in they replaced the fuel pump but it seems to me it's more electronic
Sounds like this could be a transmission or computer
issue, if your "limiter" is a rev limiter then your transmission could
be slipping and causing the limiter to engage, if Your "limiter" is
actually a speed governor then this could be normal. You state it
"flattens out." If you means if looses power then check for a
restricted exhaust or a slipping transmission.
The best thing to do is to take it to your dealer or an ASE certified master technician who specializes in motor homes. You can search for an ASE tech near you by going here: