87 suburban issues

We have a 87 suburban with the 5.7 back here in MISS, and she's running rough, she doesn't want to idle and when it does idle the RPM's constantly rise and fall, after fluctuating a few times it dies.
It also seems to be running rich, if I punch the gas in gear it might rev a little but if I let off the gas a little it will raise the RPM's to where they should be.

It seems to rev fine in neutral and park, the water pump was replaced 3 (?) years ago, and it has a coolant leak where the bottom hose on the radiator meets the block.

I'll add more info when I get to my computer (tonight)
Any input is appreciated

Edit: forgot to mention its fuel injected, and we replaced the injectors a few years ago

 

Sounds like a vaccum leak

 

I'll have to check that tomorrow, thanks Doug.

 

Check your Idle Air control valve, its probably sticking..

 

this.

 

x3

 

allright, thanks jason.
if it's sticking do i just shoot it with carb cleaner?
i pulled the air pump for the smog system since it wasn't hooked up, to plug it i'm gonna use a big bolt ( if we have one, if not then i'll make a wood plug), would it hurt anything to put some silicone on the threads to help seal it?

 

i pulled the IAC valve and it looked like this


i cleaned it with carb cleaner, and it looked cleaner, but i think it's stuck in the position, i reinstalled it, did the IAC reset, and it still runs funny.

after lunch i'm gonna unhook the TPS and check for vacuum leaks.

 

i haven't checked for vacuum leaks, but i did some reading and found out that i can test the IAC valve when it isn't in the TB, so i did and it didn't move at all so i'm assuming that that's the problem.

 

Just took it for a drive with the valve removed, it will bog with anything over a very light touch of the pedal, until its revving pretty good (no tach, but it sounds about halfway to redline) , once you get it passed that point you can floor it and it will slowly and smoothly accelerate.

 

Forgot to say that the idle smoothed out after it warmed up, but it was idling fast.