How to remove a broken off IAC valve from the throttle body of 1994 GMC Sierra 4.3 liter? The threads are stuck in the inlet of the body

if accessible from a good angle Need to drill in to the broken part in the throttle body using a drill bit a bit smaller then the IAC thread as close as possible to the throttle body thread U need rethreading tap similar to the IAC valve if available in size and thread run thru to clean the throttle body thread and replace with new one if no access to it need take out throttle body U have to take Ur time.
Good Luck

Its located right on the throttle body. If your talking about the air intake temp sensor, thats mounted by the air filter or in the plastic tube that goes off the throttle body to the air box, its a 2 wire hook up. The idle air control "iac" is located on the throttle body side. "iac" idle air control. "ait" is air intake temp. 2 totally diff sensors.

You may have a body throttle position senson. You need a scanner to confirm that. You may have a vacuum leak somewhere around the throttle body. You may have a fuel pump getting weak so I would check fuel pressure. You may have an EGR valve that is partially stuck open.

First check for a vacuum leak. Any small loose hoses in the engine compartment? If not, suspect the idle air control valve. I have pasted test procedures for the iac below. Be careful not to confuse the tps with the iac. The tps is centered on the ybro5ttle body. The iac is more on the perimeter. An additional test I do after checking the valve is to plug it back in while it is still off the throttle body and verify that it actuates a little when the key is turned on. It should back up a tad to allow idle air through the passage for starting.

TESTING
Disengage the IAC electrical connector.Using an ohmmeter, measure the resistance between IAC terminals A and B. Next measure the resistance between terminals C and D.Verify that the resistance between both sets of IAC terminals is 20-80 ohms. If the resistance is not as specified, the IAC may be faulty.Measure the resistance between IAC terminals B and C. Next measure the resistance between terminals A and D.Verify that the resistance between both sets of IAC terminals is infinite. If the resistance is not infinite, the IAC may be faulty.Also, with a small mirror, inspect IAC air inlet passage and pintle for debris. Clean as necessary, as this can cause IAC malfunction.


Fig. Fig. 2: Using an ohmmeter, backprobe terminals of the TPS sensor to check for proper resistances



Fig. Fig. 3: The TP sensor and IAC sensor are usually located at the side of the throttle body



Fig. Fig. 4: Idle Air Control (IAC) valve wiring and terminal identification
REMOVAL & INSTALLATION

Disconnect the negative battery cable.Disengage the electrical connection.Remove the IAC valve. On thread-mounted units, use 1 1 / 4 in. (32mm) wrench and on flange-mounted units, remove the screw assemblies.Remove the IAC valve gasket or O-ring and discard it.To install:
Clean the old gasket material from the surface of the throttle body assembly on the thread mounted valve. On the flange-mounted valve clean the surface to ensure proper O-ring sealingInstall the valve with a new gasket or O-ring. Tighten the thread mounted assembly 13 ft. lbs. (18 Nm) and tighten the flange mounted attaching screws to 28 inch. lbs. (3 Nm).Engage the electrical connector to the IAC valve.Connect the negative battery cable.

can be a few problems but the most common is fuel filter clogging---the others are egr valve carboning up [remove and clean carbon with a strong carb cleaner ]--fuel pump check fuel pressure--pcv valve --cat converter clogging--air filter -throttle body/carb needs cleaning--or tune up these are a few

may just need cleaning with carb cleaner.

here is 1996, oldest I have:

Section 03-14: Engine Controls, Electronic 1996 Taurus, Sable Workshop Manual
REMOVAL AND INSTALLATION Idle Air Control (IAC) Valve Removal

1. Disconnect battery ground cable (14301). Refer to Section 14-01 .
   

1. Disconnect the engine control sensor wiring (12A581) from the idle air control valve (IAC valve) (9F715) at the idle air control valve electrical connector.
   

1. Remove the two idle air control valve retaining bolts.
   

1. Remove the idle air control valve and idle air control valve gasket.
   

Installation

1. NOTE: If scraping is necessary, be careful not to damage idle air control valve gasket surfaces, or drop material into intake manifold (9424) or throttle body (9E926) (depending upon application).
   
   Clean idle air control valve gasket mating surfaces.
   

1. To install idle air control valve, reverse Removal procedure.
   

1. Tighten the idle air control valve retaining bolts to 8-12 Nm (71-106 lb-in).
   

Check your Idle air control (IAC) valve wire leads. It's located on the throttle body, the other thing to is it may be dirty and will need to be cleaned with throttle body cleaner. That is just simple cleaning out the throttle body through out, paying attention to the IAC passage way in the throttle body intake. Once you cleaned out the carbon that should help your idle problem, the other thing that would cause this a dirty EGR valve and it's stuck. The EGR can also be cleaned with Throttle body cleaner by removing it and reinstalling it once all the carbon has been cleaned out. replacing the fuel filter also would not help and that is located in the inside frame rail under the drivers side and takes about 20 min to replace. Start with the simple and replace the fuel filter and clean and inspect the IAC at the throttle body. Good luck and keep me posted.

IAC-passenger side of throttle body.IAT-located in the plastic intake duct directly after the air cleaner and before the throttle body.
hope this helps?

It sound like your idle air control (IAC) valve is dirty and the fuel injectors. Try cleaning the throttle body and IAC with throttle body cleaner, if it's really bad you may have to use two cans of throttle body cleaner to make sure you have all of the carbon and varnish cleaned out. If this does not help, then there is a good chance that the IAC has gone bad and needs to be replaced but also check the wire harness to the IAC and TPS on the throttle body. Good luck and hope this helps and it would not hurt to replace the fuel filter also.

It is most likely the EGR (Exhaust Gas Recirculation) valve.
The valve is supposed to close when the car is idling and open other wise.

Inspect it / Replace it.

Hope this helps!