RPM Drop?

[SKY]

Just tonight after the snow storm today, I recognize my rpm drop when I put in neutral. From 800 normal. down to 600, 400, 200, then light slowly goes darker and the car (or the engine) shake. Sometimes it bounce back to 600rpm..and drop t0 400, 200 again......is like when the car is shutting down. It goes normal when I was driving, just when I stop at the light, putting neutral, the rpm goes weird.

What's wrong?!

 

[NCZ13]

subbing

 

[SKY]

subbing

huh??

 

[zoomzoom510]

could be your IAC unit. sits ontop of the throttle body. it compensates for the load or electrical load on the engine. or system itself. its basically an electronic choke . it communicates with the ecu. check for 12v signal to grey or white wire. i had an issue with idle when installed the turbo. and i wired the haltech wrong and i cut the wrong wire which is the 12v signal to teh IAC idle air control. and it had zero signal. cause it was an open circuit.

basically it has two wires coming out of it. check for either or for 12v voltage. and the way to test it is .. have someone in the car turn on the ac or heater. if the multimeter drops voltage u know its getting signal. but you have to make sure you are testing at the right wire the one that communicates to and from the ECU. or you can use an led. light emitting diode. and back probe it. and do teh heater and ac test. what should happen is when you turn the ac or heater on. the light should turn on . if it dont you have no signal and you could have a loose or open circuit. cut wire.