So the past few mornings I've had some interesting idle quirks with my 2004. I have two tunes that came with the car, a hot and a cold, and as the temperature has been falling, I tried the cold tune out this morning to see if that would change things and it does not appear to have made any difference. The issue I'm having is more or less a high idle hang and then a funny surge after it. I'll start the car up first thing in the morning and it will idle fine, even the next few stop signs it seems like it knows what it wants, but after warming up just a bit, when I clutch in to come to a stop the idle will hang high around 1500 rpm, then slowly drop to around 800, then quickly surge up to 1200 or so briefly before dropping back down around 800. You can even tell when driving that it's holding the IAC open or something, because it will still pull some with my foot entirely off the gas before it kicks into "idle" mode and tries to slow it down. This would normally make me thing the IAC was flaky, but it seems like the car is fine when it's warmer outside (probably 40-50+). My next thought was maybe it was losing the TPS calibration so it doesn't know where 0% is? I noticed when I had the tuner plugged in yesterday that the battery readout was only 11.8 or so, but it faithfully starts the car every morning with very little drama or cranking. Didn't know it maybe it was drooping far enough overnight to lose the TPS memory or if something else was going on. Anyone have some ideas of what all to check while I'm diagnosing? It drives fine aside from the idle issues.