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Jumpy idle when IAT is plugged in?

ninnyGTP

ninnyGTP

New member
Yesterday I decided to have a little fun and was doing a couple WOT runs on the freeway. Well when I was done I noticed the idle was HORRIBLE. Thought maybe vacuume leak or MAF but both checked out. So I popped the intake piping off to check things out. As soon as I did that it idles and starts up fine. Plugged everything back in and idles like hell again. Unplug the IAT sensor and runs fine, plug it back in and jumpy idle. Alright, bad IAT, swap in a spare that I have and same issue? Am I missing something haha
 


I should also note that with the IAT sensor plugged in and you give it some gas rather than going up in RPMs, it goes down and nearly stalls
 
You may have a wire shorted on the return signal from the IAT, so when it's not plugged in, there's no short. Check the wires for the MAF, TPS, and IAC valve. Also, try placing a 10k resistor across the pins for the plug to the IAT and see if you get the same result.
 
The IAT has a little to do with idle. It supplies the correct air temp to the PCM for it use in conjuction with the ECT in order to determine the idle speed, amount of fuel etc etc.

When unplugged your IAT temp should read abotu -40F as a default the car runs rich.

Do you have a method to read the sensor? Aeroforce, scan tool etc?
 


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