ICV means?

Yes, I take away half the MPG loss from high idle by turning my car off at lights and never letting it idle...that said, I'd look for vacuum leaks. That reduced my 1,450 idle to 1,200 at it's worst, unless you think 650 is worse...at least the worst is no longer 550 and going into gear risks stalling.

 

Think it could be a bad coolant temp sensor? If you have a scanner you can compare what the IAT reads vs ambient temps, as well as see what the coolant temp sensor is reporting.

 

Great test when the car has been sitting.

I've seen it be off as a car heated up before. For that you'd need a "laser thermometer". Really, it's an infrared sensor, but the laser is for us to aim.

Come to think of it, I need to redo that test.

Sure, my short ram air intake makes it so I can double air at WOT, but can it really get triple the air now? No. Sorry, splitting my attention to my car as I think about yours.

On the 7th generation is the IAT (intake air temperature sensor) combined with the MAF? Other than live data - can you do that with OBD I? - and known norms, testing MAFs require a scope, but the IAT just needs the laser thermometer.

 

You didn't take off the little 2 screw plate at the end did you?

 

Looking up charts of resistances for certain temperatures for your specific car and a laser thermometer or a live data and a laser thermometer will work for the IAT.

Be sure to test at more than one temperature! Mine looked good near outside temperature but as the car heated up it quickly moved out of the resistance, and live data range of acceptable accuracy.

 

No MAF on 7th-gen, MAP-sensing with separate IAT in the air-box.
If IAT and ECT resistance-curves are correct, then the only way the car can idle faster than idle-speed is that it's getting extra air somehow.
A vacuum leak. Measure vacuum in the intake-manifold with warmed up engine and with that number, we can proceed from there.

 

And your temperature gauge didn't just start spending most of its time not being able to rise much above the "C," after it used to go up to a little under halfway and stay there, no matter what the conditions?

Thermostat likes to stick open in these cars, and that will usually keep the idle too high.

Can you post a pic of the part you cleaned and replaced?

It might all coincide with a thermostat failure.
Maybe...

 

Thanks for the good information and I will check for vacuum leaks or additional air coming in from somewhere.

I replace the idle control valve located on the bottom of the the throttle body with the green part.

I don't have a temperature reader but will try to check coolant temp sensor and Intake air temp sensor.

Appreciate the good info / leads

 

The IAC has a valve that opens and closes based on engine/coolant temp. I would think you maybe cleaned it too well and the valve does not have enough lubrication to open and close. depending on how long its been since you cleaned it, you may need to either lube it or replace it. but since it was fine before and high after id say that where you need to look.

 

Weazler,

Good point! I did get one for pull a part and cleaned it pretty good. Can I lube it some or buy another one? Is there a way to lube without taking TB off?

My next thing is to replace the coolant temp gauge as recommended from previous post.

Thanks for you help