i have a 98 12v and i keep having to pump the primer in order to keep it running replaced lines from tank to rail and from rail to motor no way to check fuel pressure but i am thinking lift pump any idea's

 

Just about answered your own question. Need to get a fuel pressure gauge on it. You can get simple test only gauges not intended for full time mounting at any auto parts store.

 

yeh replaced it still has same problem??????????????

 

if fp is good then start looken for where u might be sucken air, loose fittings,clamps

 

Check for air leak around your fuel heater and the top of the fuel tank module.

Had a 99 doing similar, steel hard lines to the tank module were rotted off at the tank.

 

It does not hurt to check / fix / replace fuel lines & hoses .
But check fuel pressure .

 

thanx guys but dumb question how can i find a air leak i.e spay something or dump a fluid on it because it is in vacum and not positive presure from fuel tank to lift pump?????

 

What I do is get an extra fuel tank cap , install a metal tire valve [ shrader valve ] , then put about 2-3lbs of air pressure into tank , then check every inch of line & hose , do forget the top of tank , its common for the lines coming out to rust .

 

ok replaced lines lift pump no air leaks and still does it i am baffled please any help i even pulled sending unit out of tank and looks and works good but still stalls then i have to pime and works for awhile

 

I haven't seen any responses with test results , that's how things are fixed , testing tells what to replace .