I try starting my truck. It starts sometimes very badly. When I hit the gas does nothing. It doesn't idle and shuts right off. If I hit the gas like a mad man it stays started very slowly like it still will die. I changed the fuel pump and have that working now. Drained the gas cause it was sitting a while. I've cleaned almost everything except the fuel injectors. If I spray gas into the throttle body it starts fine till the gas runs out. Please help

 

Check to see if you have the correct fuel pressure at the fuel rail, unfortunately I do not know that number. If you have enough fuel at the injectors, then see if the injectors are firing and fuel can get to the cylinders.

 

do I take off everything to get to the injectors or is there an easier way to test them

 

89 I think would have a schrader valve test port. You can rent a fuel pressure tester from most auto parts stores. A schrader valve looks like a tire valve stem, and should be on the fuel rail that connects to the fuel injectors.

What engine do you have?

Did you replace the fuel filter when you did the pump?

 

You changed which fuel pump? There is the one on the frame rail and one in each fuel tank.

 

Take a look at this, as it's the in-tank pump. I'm pretty sure you only replaced the frame mounted one.