i have a 1998 gmc 1500 will run when i pur fuel in throutel body but then dies

Sounds like your fuel pump is shot. Also is it a vortec engine? If so I don't advise putting anything in the throttle body like gas. If it just happens to backfire thru intake you will be replacing the intake too. It's plastic and will blow into pieces. Still finding parts of mine in the back yard.

Try a fuel pressure test first. The fuel pump is a pain to get out. If the pressure is low try the filter first. If the pressure is still low I recommend disconnecting the line at the fuel filter and using what ever life the pump has left to drain the tank. It's also easier to take the drive shaft out. BTW take your VIN to the parts store. '98 GMC fuel pump's changed have way. Early models have the steel lines the newer one has hoses to the plastic ports on the pump, need the quick connect hose disconnect tools. You can look under the box over the frame at the pump to see which pump you have.