Hi, I am new here. I have a 97 cummins 5.9 in my motorhome. If I let it sit overnight or longer, I have to go through the prime steps to get it to start. Turn the key on and bump the starter 3 or 4 times to prime the pump. Also, if climing a hill or going 70mph down the freeway it cuts out like it is running out of fuel. It completely stalled on a hill too. I had to reprime it and away it went after cranking for 20-30 seconds. The only thing I have done so far is change the fuel filter. I dont want to just throw money at it, Any ideas? Thanks. And you have a great forum here.

 

can you check your fuel pressure? it sounds like you have some bad fuel lines. they are pretty straight forward to change but not a real easy job.

 

You have to either check the fuel pressure or throw parts at it.
Instructions> Checking 12 Valve Fuel Pressure

 

I'll check the pressure. I've seen where they should be in another thread on here. Hope its just an easy line change. Thanks alot.
Shane

 

i would put a overflow valve in its gonna need changed any way

 

As stated, check the fuel pressure, you could have a weak lift pump, an Overflow valve or bad fuel line issue.