I went to set my minimum air using tuner pro to monitor the rpms. I inserted a paper clip and grounded the AB terminals turned on the ignition and let it set in this diagnostic mode for a good minute. Turned off the ignition disconnected the IAC, removed the paper clip and started the motor. The idle went to 1300 rpms. I can back the minimum air screw all the way until it's no longer contacting the throttle lever and I still get 1100 rpms. That tells me that I am pulling air in somewhere but a propane/starter fluid test turned up nothing.
Recently I found out that if you start the motor with tuner pro and a laptop connected you risk damaging the ECM. Did I do that? When I connect the IAC back up while the engine idles the computer pulls the idle to 650 but it idles rough which is the original reason for checking the IAC. The throttle body is clean inside and out and the IAC along with anything else you can imagine on the engine is new.
Is my ECM damaged? Even my tps voltage has changed and I never touched it from my original setting of .55v it now reads .39!

 

set the tps back to the original setting and if it happens again get a new one

 

This means that your ECU didn't close the IAC when you did your minimum air test and could only get to 1100 RPM.

to ALL TPI Guys: An IAC is only an air inlet! Rough idles, low vacuum, rich/lean idles are NEVER the IAC.
Unsteady idles usually mean the iac is fighting a fueling or spark hardware problem.
Stalling, low or high idles, or low idle when cold, high idle when hot, or the occasionally intermittent high/low idle can be the IAC.

 

before fualting or adjust any sensors make sure your reference voltage and grouds are good

 

Made an error. I disconnected my IAC after I had turned off the ignition. This kept the IAC open. Once I changed my procedure everything worked out fine, except that my idle still is not what I think it should be.
Checking my grounds next and I will keep you posted.

 

Hopefully, you're using a diagnostic tachometer to set the minimum air RPM, and not the dash-mounted unit. They are notoriously innaccurate.

 

I have been on vacation skiing over the last week so I have not been able to respond promptly, my apologies to all.
I have been using my Tuner Pro software to set the IAC.

What I am noticing about the idle is that the problem is intermittant. The idle problems occur once the engine is at normal temp and it has been driven. After I shut off the engine and it sits for a while it will start and idle very rough. For instance the car ran fine when I went to do some last minute christmas shopping. Went into the mall for about 30 minutes came out, started the engine and it ran like it had 5 cylinders with a strong smell of gas. After the car is driven for 15 or 20 minutes the idle smooths out decently. I noticed on Tuner pro that the INT is really trying to lean the engine out. The O2 voltage goes way into the red zone.
After the 20 minutes of driving the INT, O2, and BLM all level out where they should be.
The injectors were replaced with new Bosch units from Kragen last April, but fuel must still be draining into the cylinders now and then.
Also one time I went to remove the gas cap and gas literaly flew out of the tank under a lot of pressure!
EVAP canister problem I thought so I cleaned the electrical connection and the gas flying out of the tank hasn't occured since. According to Tuner Pro and my GM service manual my canister is operating as it should.
The idle still is very rough on occasion with a strong smell of gas.
Could the regulator be applying too much fuel pressure? It's a stock one. The whole car is stock.

 

I'd take a look at the coolant temperature sensor. But, maybe your ECM is acting up as well (or perhaps the MAF). Some strange things are happening. Maybe try the shake test on the ECU (and then the MAF) to see if it causes a stumble or anything.