IAC sensor went south

[1992TalonESI]

The Idle air control sensor in my 1992 talon has given up...currently the car revs its self some of the time (i put a temp fix on it by cutting a hole in the intake hose)...I asked around and fixing that would be around $500...I don't want to spend that much...besides i want a cold air intake...my question is, with an aftermarket cold air intake what happens with that sensor? Wouldn't it be eliminated? and if so wouldn't the computer see a problem with that and rev its self still?

[Talon69]

not sure on that year but i have a 95 tsi awd and i put a cold air intake on it just a few days ago and all my sensors are still there along with the mass air flow sensor.

[MrZ]

1992TalonESI:
Whether you put a cold air intake or not, you need that sensor. You are talking about the one in the air filter housing, right? I really don't undertand the comment about cutting a hole in the intake hose.

Just to be sure we're talking about the same thing; there are three sensors in the air filter element. It has an air temperature sensor, a barometric pressure sensor, and an air flow sensor. You also have an idle speed conrol motor mounted on the throttle body, and a closed throttle position switch, also mounted on the throttle body. finally, you have a throttle position sensor mounted on the throttle body. They all work together.

The closed throttle position switch lets the ECM control the idle via the idle speed control motor when the throttle is closed. If that switch isn't working properly, i.e., if it's giving an intermittent signal to the ecm, it could be causing the problem.

It is also possible that your throttle position sensor isn't working properly. It can also cause an intermittent signal which can cause the engine to surge and behave a bit strangely, though this doesn't usually happen at idle.

First thing you really need to do is to check for fault codes in the ECM. There is a fault code for each of those switches/sensors.

Mark