The IAC is supposed to unscrew from the throttle body like a spark plug correct? Mine will not budge for anything.
I'm also concerned about the two missing screw heads on top, looks like they snapped off. Should I just replace this whole assembly? I can get a TB and IAC used for fifty bucks.


The black piece sticking out in my hand is the IAC correct? This is off a 305 TPI

 

Yes that's the IAC and it just spins out. They're generally good and stuck, pretty sure the assembly line used a thread sealer to prevent leaks that tends to lock them in place. Carefully clamp the throttlebody in a bench vice and use a large wrench that fits properly and they usually come loose. Light heat would probably help too.

There's no reason to believe that a used throttlebody is going to be in much better condition.

 

I use PB Blaster on almost anything that is threaded and wont budge with moderate pressure.

The only time I really crank on it is after the blaster has been applied.
That rarely happens.

Spray just a little where the threads start and give it an hour.

PB Blaster should be in ever ones tool shed.