Cleaning the Idle Air Control Valve and Throttle made things *worse*?

2000 Mitsubishi Eclipse, 2.4L, 4 Cylinder

I had some rough acceleration at times, so I got some of that spray cleaner and cleaned the Idle Air Control Valve and Throttle and now it drives a little better but the the idle is terrible. It’s a real battle trying not stall at stop lights and at start up.

On cold start I will hold the gas pedal to get revs a little high, but it revs back and forth 1000-3000 rpm, even thought I am holding the pedal steady. Once it gets warm it will no longer rev high like that, but it will stall on its own. I did spray the idle air control valve (unplugged) with that cleaner, could I maybe have fried the valve by spraying it? Any advice would be appreciated.

edit: I just realized looking at the spray bottle that I used Carburator Cleaner, CRC Brand instead of Throttle Body / AIr Intake Cleaner. Could that have caused the problem?

Type of the cleaning product is unlikely to cause much trouble, IMHO.

For Nissan, after doing throttle body cleaning you are supposed to run “idle control self-learn procedure”.

I can imagine for Mitsu you would still need to do something similar, but the actual procedure might be different… Google for it!

The throttle position sensor may be the culprit.

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Carburetor cleaner can damage the idle air control motor. The safe way to clean that type of throttle body is to remove it from the engine, remove the IAC motor, clean the throttle body and IAC port and wipe the tip of the IAC motor. Do motor spray into the IAC motor.

About 15 years ago a co-worker sprayed a cleaning product into the IAC port on a Mitsubishi 3000 GT with the engine running and dissolved the tip of the IAC motor. The IAC motor in your throttle body appears to also have a plastic tip.

Inconsistent idling can be caused by numerous things, but if you think it is a throttle valve position problem, the best way to address that as mentioned above is usually to remove the entire throttle body from the engine and clean/inspect it on the work bench. The egr and pcv system can pollute the back side of the throttle valve, and you can’t easily reach that area by spraying cleaner into the intake side of the throttle body. A throttle valve position problem wouldn’t usually cause rough acceleration tho, so I expect you’ve got some other things going on there too. Make sure you read out all the diagnostic codes from computer memory first.

Hi. I also found sort of same problem. I have a Nissan Sentra 1994 and the rpm after pushing brake was going really low. So I just 2 days ago disassembled the idle air control valve and sprayed it 6 times with CRC. now rpm is more than 1500!
I guess because that valve has electric circuit , CRC shouldn’t be sprayed on it and maybe I have damaged the valve with CRC…Any comment or thought please? thank you

It could be that you need a new IACV. It seems to be broken, not just dirty.

When I deal with cars that are as old as the two here, and they don’t idle right or run rough, I look for vacuum leaks. There are lots of vacuum tubes in cars of this era, and they are all about 20 years old and get cracked and crispy and break and leak when they get this old. If you look around there should be a sticker with a drawing of the routing of many of them. Inspect them carefully and replace anything that looks at all tired, one line at a time so you don’t mix them up.

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The old Nissans had a dual switch for throttle position. One was a variable resistor to give relative throttle position, the other was a two position switch that detected when your foot is off the gas and when you have the pedal to the floor (ISP idle position switch/WOT wide open throttle).

If you made any adjustments to the throttle stop screw, you could keep the IPS from making. Some people think the throttle stop screw is an idle adjustment screw, but it is not. The IPS has to make contact or the computer will not take over controlling the idle via the IAC.

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