Chrysler Repair: Update and question, air control valve, head gasket

Question
Hi Roland,

Hope you remember me, the volunteer here on the network with the 1997 Intrepid last week with the high idle and overheating problem. First of all a HUGE thank you as I was able to find one problem...the overheating, this was finally the other fan, on the passenger side that does not come on. It had 2 problems, the suppressive module that it's connected to was shorted, as well, the fan itself was finished as it did not even turn with a direct 12V to it. The only sad part is the high cost of purchasing another.

As for the idle, after changing the TPS I took it to a mechanic I usually trust. I was worried since you said if I get white smoke when starting it that lasts more than 1 minute (and my high idle) that it might be the head gasket; the white smoke seems to last 3-5 minutes. Two mechanics there said they were sure it's not the head gasket since I would have other problems and that's it is normal condensation...is this true or did I missinterpret what you explained to me? Even the haynes does not really tell me how to really diagnose a head gasket.

As for the idle he said it was probably the Idle Air Control Valve...funny enough this same evening I had a new check engine code, stating the Idle Air Control Valve. When I removed it I saw it was stuck open. I replaced it and read in the haynes that it would take "some time" for the computer to "relearn" the idle? How much time? I have been driving the vehicle for 3 days now, I do notice some improvement in engine performance but still idles high (around 2200-2500) when in Park or Neutral. Also if I let go of the break on an open road, it will go up to 60Km/h by itlsef, no need for me to press the gas...it not as fast to get there as pressing the gas but it eventually gets up to 60Km/h.

I did check, as you suggested, the air intakes and hoses, no leaks anywhere. There are no more check engine codes as well. The mechanic suggested that maybe the EGR is defective...this costs $250...Is it possible to have a defective EGR and not have a code or check engine light? Is it worth the risk of changing it or should I check anything else first? I figured if I go through the trouble of removing for inspection I might as well change it.

In the end I am still worried that if I change all these parts and it's the head gasket, I'm just waisting all this money and with 4 kids, we really cannot afford it.

I apprciate your time and help and promise this is the last time I bother you!

Have a nice day Roland,
John

Answer
Hi John,
Thanks for the update. On the white smoke question, you can try letting some of the smoke condense on you hand or a metal surface and then smell it for an odor of radiator coolant. Or you will notice a loss of fluid from the recovery bottle, gradually. Or if those raise suspicions an auto radiator shop can test for exhaust gas entering the coolant system with a sensor attached to the radiator cap opening. All of these would be a way of distnguishing normal condensation from a head gasket leak.
On the iac valve, I am not certain about the learning time, but 3 days seems like enough. You might want to consider removing IAC motor and cleaning out the passageway into which it fits with some solvent in case it is cruddy. Also, check the four wires near the iac for possible insulation melt-through and consequent shorting together of the wires.
If the egr is defective it is usually such as to cause a reduced or inability of the engine to idle. So I would not spend anything on that at this point. It can be tested with a vacuum pump applied to the hose connector on the top of the valve while the engine is idling, which opens the valve, and will cause the engine to stumble or die. If it does, then valve is o.k.
So I would still focus on the iac which seems to be the major issue remaining.
Roland