Idle Air Control (IAC) Valve

[iampinoy]

I had a previous post asking if the 2002 4Runner has an Idle Air Control (IAC) Valve. Brian R. replied that there is one and it is located under the air cleaner hose. However, I can't seem to find where it is. I used to own a 1999 4Runner and I know that it had an IAC valve mounted on the underside of the throttle body but the throttle body on the 2002 4Runner is designed slightly different. I checked the same location on the throttle body where the IAC valve is located on the 1999 model but I didn't see anything that resembles an IAC valve on the 2002 model. I didn't even see any wires or connector that plugs at the bottom of the throttle body.

I searched the Internet hoping to find some information about this but I was unsuccessful.

Brian R., if you get the chance to read this new thread, could you please double check the info that you gave me in my previous post. If there is an IAC valve on the 2002 4Runner, could you please tell me its exact location. You also suggested to check the EGR valve. I'd appreciate it if you could also tell me its exact location? If someone else out there knows for sure where these components are located, please let me know.

I am still having vibration problems when my 2002 4Runner is in idle with the transmission in gear. The vibration can be felt on the steering wheel and driver seat. There were times when it felt like the engine was in the verge of stalling. I have already replaced the air filter, spark plugs, checked the resistance of the spark plug wires, checked the primary and secondary coil resistances (all three ignition coils), checked the condition of the Mass Air Flow (MAF) meter, and cleaned the throttle body around the butterfly valve. The engine rpm (as read from the dashboard's tach) is 700 rpm with the transmission in PARK or NEUTRAL and goes down to 600 rpm (sometimes slightly below) when the transmission is moved to DRIVE. The rpm raises up to 650 when the Air Condition is turned on and the vibration smooths out quite a bit. Added load such as turning the steering wheel, stepping on the brakes, and turning the headlights on do not seem to have an effect on the idle or the vibration. I also mentioned in one of my previous posts that I read somewhere that the 4Runner's idle rpm should be 700 +/- 50 (engine at normal operating temp). Does anyone know if this specification only applies when the transmission is in PARK or NEUTRAL or does it also apply when the transmission is in DRIVE. My 4Runner's current mileage is just a little over 42,000.

Also, can anyone tell me where I can purchase a 2002 Toyota 4Runner Repair Manual on CD?

[Brian R.]

The 1996-2000 5VZ-FE have IAC valves that are separate parts. The 2002 has a motor assembly fulfilling the same function that is integral with the throttle body and you have to replace the entire throttle body.

There may not be an EGR valve on that engine. I can't find any reference to one.

Sorry for the confusion. Many times a problem can be caused by many parts. Those that don't exist on a particular engine can be easily ruled out.

[iampinoy]

Originally Posted by Brian R.

The 1996-2000 5VZ-FE have IAC valves that are separate parts. The 2002 has a motor assembly fulfilling the same function that is integral with the throttle body and you have to replace the entire throttle body.

There may not be an EGR valve on that engine. I can't find any reference to one.

Sorry for the confusion. Many times a problem can be caused by many parts. Those that don't exist on a particular engine can be easily ruled out.

Brian, do you know of a way to troubleshoot this motor assembly or maybe even clean its components. What about its location on the throttle body?

[Brian R.]

I just passed on information I got from a parts counter man at Toyota. All he said is that it is internal to the thottle body. Since it is a motor, it must have an electrical connection. Sorry, I can't be of more help.

[Tuba]

Hi, I am new here, this is my first post. Wouldn't worn Tranny mounts/Engine mounts give the same symptom? I had a similar problem with my 87420SEL. I replaced the Tranny mount and Engine Mounts and she idled smooth.

Just my 0.02 worth.
Tuba

[iampinoy]

Originally Posted by Tuba

Hi, I am new here, this is my first post. Wouldn't worn Tranny mounts/Engine mounts give the same symptom? I had a similar problem with my 87420SEL. I replaced the Tranny mount and Engine Mounts and she idled smooth.

Just my 0.02 worth.
Tuba

Tuba, thanks for your 0.02 worth. My 4Runner is a 2002 model and I don't think the transmission/engine mounts are already worn but, it's something worth checking. There may be something loose. I'll let you know.