Starting issues on '03 Yukon

[maduro]

Hey guys. So here's my situation. Yesterday my wife went to start the truck & it took 3 tries. Each time it turned over & didnt start. Started on the 4th try. She drove it for about 10 minutes then turned around & came back home.
Today while idling at the kids school she said the rpm's were bouncing around from 0-3k, freaking out. She wanted to make sure she didnt get stuck in an awkward spot so she tried to park & when she put it in reverse it died. Let it rest for a few minutes then it started up again after a few tries. All of this comes on the heels of me doing the following & of course she thinks its my fault:

New CAI
LED interior conversion
LED tails
HID fog install: 35w morimoto's

The only thing I can think that I may have screwed up is the ground wire from the HID relay harness. I attached to a screw that's located under an inside edge of where the hood sits when closed. Of course its a painted surface but now that this is happening I have some doubts. I hope someone here can chime in. The battery is an Interstate that is about 3yrs old. I havent been home yet so I haven't tested the battery. Based on what I said here can someone say if its the battery or alternator?

 

[JKmotorsports]

Recently installed new CAI. Check to make sure the intake tube at the TB and MAF are on tight and secure. A leak in this area can cause the symptoms you are having.

 

[maduro]

Thx JK. I just popped the hood & checked the intake tube at the TB & it was loose a bit so I tightened it. I was hoping that was the issue but don't think so. I started her up & let her run for a bit. I shut off all accessories & didnt notice any dip in rpm's or lights flickering. As soon as I turned on the AC it immediately dipped to 500 rpm then even lower before ticking up. It would dance between 200-500 rpm constantly. I shut off the ac & its fine. I checked the battery & the charger showed 12.9-13. I believe thats good but I have to google it to be sure.
All this happened while i had her in park. I'm sure it would've stalled had it been in gear.

 

[delta579]

Check your Idle Air Control (IAC). Symptoms you describe are classic. Remove IAC and clean the seating area and the IAC plunger tip. Check for any vacuum leaks as well. Check Mass Air Flow (MAF) for damage/contamination and the connector. It's not hard to damage a MAF filament when handling it. Hope this helps.

 

[Gmcturbo]

Put the stock intake on and see if it goes away. Probably a bad fuel pump, you need a scan tool and scope. They are good for fuel pressure regulators leaking also