My truck started misfiring on multiple cylinders a few weeks ago, so I changed the plugs, wires, cap and rotor. Now the misfire is gone but it won't run unless I keep it above 1500 rpm, even after 5 min. I dropped the tank, pump is functioning, but here's a couple questions.

1. There is pressure at the rail, but when I press the schrader valve with a screwdriver the gas only shoots up about 2 inches. I thought there should be more pressure than that.

2. I removed the IAC and turned the key to see if it is functioning and the tapered end end fell right off the rod when it extended. I put it back together and the same thing happened when I hit the key again.

I ordered a new pump which I'll install anyway, but is this normal for the IAC?

 

Why a pump? Could be your pressure regulator.

Here is what mine used to look like on the inside:



The regulator acts like a secondary filter. I would also check to see if the injector inlets are plugged.

 

Do the injectors just pull out after removing the clip?

 

To pull the injectors perform the following steps:
1) Alleviate the pressure in the fuel system
2) Remove the clip that holds the fuel line to the fuel rail
3) Remove the bolts that hold the fuel rail in place
4) Lift up on the fuel rail, gently removing each injector from its bore
5) Remove the clip that holds the injector in place

When reinstalling the injectors, it is usually a good idea to replace the upper and lower O-ring. Coat each O-ring in light oil before installing it back into its bore.