Need to find where the fuel pump shut /reset is loc 98 e350v/10

Fuel shut off switch may need to be reset. A friend of mine had it trip when he had a flat tire some years ago on ford car. The reset on his was behind the plastic piece to the right of where the video below. Video below shows fuel shut off/inertia switch on upper floorboard passenger side.
Inertia Switch Explained Removed and Replaced 98-12 Ford Ranger - YouTube
2002 Ford Ranger Fuel Cutoff Switch - YouTube
You can try swapping out your fuel pump relay to make sure the relay is not bad. Below link may help
1999 Ford Ranger Fuel Pump Relay, Fuel Pump Fuse & Starter Fuse Location - YouTube

Then the pump is bad or there is no power to the pump.

Ford

get your car fix right now

Does it crank and crank for awhile? Then finally start? Sounds like a bad fuel pressure regulator. Bad news. It's in the tank part of the fuel pump assembly. The valve in the regulator is bad allowing the fuel that's in the fuel line to drain back into the tank instead of maintaining positive pressure, so when you shut it off , it drains and then has to repress urge the entire line . Before u start it from now on, key it on and count to 10 then start it , let the fuel pressure build back up.

Well most engines have a mechanical pump on the engine, but the E350 models used for motor homes and box vans also use an electric pump in the tank. The pressure rating is still 5-8 psi like the mechanical pumps.
Have you replaced the inline filter ?

If it idles but bogs when the accelerator is pushed, it has carb issues(if it has been sitting for a long time probably has carb issue) or low fuel pressure. If its low fuel pressure then it could be a bad/clogged fuel filter, fuel flow problems from the tank to the fuel pump, or a bad fuel pump.

PRESSURE RELAY SWITCH ,FUEL PUMP IN THE TANK YES ,YES BUT TRY THE FUEL RELAY SWITCH FIRST ,BECOSE WHEN IT GOES OUT IT SHUTS THE POWER FROM THE FUEL PUMP

It is in the tank,there are too many fuel pumps on ford to know a part number,napa can give you the right one for the van with your v i n number.

if it was me i would start with a new fuel filter and some STP gas treatment if you let it sit for a long time there maybe water in the gas tank and try these websites to see if they have your motorhome listed its www.autozone.com and the other one is www.alladtadiy.com if all fails stop by your local library and get your hands on a Haynes auto repair manual for your motor home

Do you have any of you fuel lines close to the exhaust? (vapor lock)