[100_Percent_Juice]

In a nutshell

Problem
All problems are inconsistent
While in Vegas - High idle(not wandering) 1k, 1.5k or 2k RPM at times
Back in Reno - Idle dropping very low(200rpm)for a few seconds before returning to norm.
After ECU reset - Car ran fine for weeks
Now High idle problem is back

Steps already taken
New fuel
Reset ECU
Cleaned air filter
IAC Valve was cleaned(by me) about 2.5 years ago so I didn't think it would be the issue

Car Modifications(all mods are years old)
gutted up-pipe
3" TBE w/ high flow cat
COBB OTS stage 2 CA gas map(has been for years now with no issue)
K&N oiled air filter



Story in detail

About a month ago I drove down to Las Vegas and while I was down there my car started to act weird. While I would be sitting at a stop light my RPMs would be stuck at 1k or 1.5k or even almost 2k. It would not bounce around or fluctuate but I noticed it to be different at different times. Then I got a CEL and had Kragen check it. The code said what I already knew "idle higher than normal" or something like that.

Then the car started making a loud belt driven sound as if I had a supercharger on the car. It was easy to hear that this sound was coming from the A/C compressor. I could mess with the A/C knob and it would stop the sound some times. The sound would start on its own at random times yet the A/C works perfectly so I don't know why it would be making that sound. I couldn't do anything about the problem when I was down there so I ignored it and just drove easy until I got back home.

I assumed that I either got some bad gas during the trip or I needed to clean my air filter since I was in a massive wind/sand storm on my way to Vegas. I also thought that I might have gotten sand in parts of the A/C compressor and that could be causing the sound.

I got home, cleaned my air filter(it's a K&N oiled filter), cleaned all the sand out of the engine bay(all I could get out). The problem now was the opposite of what I was experiencing in Las Vegas. In Reno my RPMs would drop so low that I could barely hear that my car was running. The RPMs would drop really low for around 2 seconds and then come back up to normal. This would happen every time I would take my foot off the clutch to come to a stop.

I was out of ideas so I figured that the A/C compressor might be messing up the idle so I removed the A/C belt. The noise stopped but it had no effect on the idle problem. I have deemed this problem completely coincidental and unrelated to the idle. I unhooked the battery and reset the ECU. The car started up and has ran normally for weeks until today. The high idle problem has returned but is not as severe. A lot of threads point to the IAC valve which I have cleaned once before a few years ago, so I don't think that would be the issue. I have also read about the cruise control cable causing the high idle. I have yet to mess with that. Any other ideas about what could be wrong?

Thanks