First update for April 2012, a bit later than I anticipated but I finally got around to write it! In this update, I will illustrate how to go about cleaning your Acura RSX's IACV (idle air control valve) and the throttle body along the way. Why should you perform this cleanup? The IACV and throttle body are both mechanical parts that interact with your car's air intake system. In an ideal world, everything would be clean and maintenance probably would not be necessary. But we live in the real world where your car's air intake system sucks up microscopic particles, dust and other contaminates. Overtime, this will build up and inhibit your IACV and throttle body from working efficiently. When this happen, a couple of side effects follow. You can have erratic idle and stalling issues (i.e. idling toggling back and forth between 500 to 1000 RPM) or your car simply stalls out shortly after it is started. This happen because your engine is not getting enough inflow of oxygen to mix and combust with the fuel injection system, thus, stalling out. To fix this, you need to remove the throttle body to clean the system and free it from contaminants that jams up the mechanical parts of the throttle body.
First, you'll need a cleaner. There are several products you can use to clean your IACV and throttle body. I heard un-chlorinated brake cleaners to other solvents. To save the trouble, I just picked up a can of Throttle Body and Air Intake Cleaner by CRC, available at your local AutoZone for around $4.00 a can.
Pop open your hood and remove your stock air box. Release the clamp on the air tube connecting from the air box to the throttle body and then remove the air tube. Use a plier to release the clamp that's connecting a small rubber tube from the engine block to the air. Let the tube hang from the engine block but make sure it's disconnected from the air box. Remove the air box by unbolting five 10mm bolts. Four of these bolts are easily accessible, the 5th one you will need to remove a rubber grommet to access:
With all five bolts removed, carefully lift the air box up and maneuver it out of its bay; dislodging it from the stock air inlet tube. Next, remove the stock air inlet tube by unbolting a 10mm bolt located on the radiator frame.
The stock box removed:
You don't need to remove the entire air box assembly out of the engine bay, just the cover. I used photos from my Injen CAI installation guide to illustrate this step.
Next, you should be able to see your throttle body in full view:
Remove the engine cover by unbolting two flange bolts (6x38), then lift the cover up carefully and set it aside.
Next, unbolt two 6x12 bolts that's holding the throttle body wire casing to the throttle body and carefully set it aside. This will reveal the metal cable that operates the throttle body valve:
With the throttle cable exposed, it's time to remove it from the throttle body itself. To do this, you'll need to wind/unwind the throttle body valve rotary mechanism until you and free the throttle cable from the valve rotary. If you look at the end of the cable, you'll see a metal cylindrical notch attached perpendicular to the cable and inserted into a corresponding hole on the valve rotary. Maneuvering the cable out of the rotary can be tricky so you may want another set of helping hands:
Next disconnect the three wires from the throttle body. You may need to use a needle nose plier to pinch and pull out the plugs, especially if the plugs has never been removed since the car was manufactured.
Unbolt two 8mm flange nuts and two 8x40 flange bolt from the throttle body. They are arranged in a "criss cross" pattern, i.e.
flange nut - flange bolt
flange bolt - flange nut
You may need an angled socket/ratchet set to reach the lower 8mm flange nut and flange bolt. Set the nuts and bolts aside and carefully detach the throttle body from the engine block.
Carefully remove two hoses located near the bottom of the throttle body. Be sure to have an empty bottle ready to catch the reserve coolant, otherwise it will leak to the ground. Alternatively, you can use clamps to keep the coolant from leaking. Once the tubes are separated, you can remove the throttle body from the engine block.
Now we are ready to remove the actual idle air control valve and clean it. The idle air control valve is the piece located at the bottom of the throttle body:
To remove the idle air control valve from the throttle body, unscrew two 5x25 screw+washer set. Again, this may be difficult, depending on the last time this maintenance was executed. With the IACV unit remove, you may take the time to clean the throttle body valve. Spray the cleaner onto the valve liberally and scrub it with used (but clean) toothbrush. Any small brush will do, but I find toothbrush pretty effective. Repeat the process until the valve and the opening, front and back are clean. Be sure to open the valve and clean the crevices in between as well. Since the cleaner evaporates quickly, clean small areas at a time but repeatedly until all the dark gunk is removed.
Next, do the same for the idle air control valve:
Again, spray the valve liberally and scrub the crevices with a brush until all the dark gunk is removed. If you need to replace your idle air control valve for any reasons, you can order it using part number 16022-PRB-A02. It's about $190.00 from online Acura parts dealers.
Be sure all parts are dried before reinstalling. Reinstallation is reversal of removal. What you'll notice once you performed this maintenance is instant difference in throttle response (i.e. accelerating). You'll also notice that your gas mileage has also improved - significantly if you haven't cleaned either your throttle body or idle air control valve in a while (i.e. over 60,000 miles).
If you have any questions, please feel free to comment.