Calling all 5.0 experts. Need some help.

OK I finally got my car to run a KOER self-test, after fixing the NDS.
The thing idles like it has a .700" cam in it. The idle will go from 900-1100RPM, and will smooth out if you hold it at about 1400RPM. Then it will hang for several seconds.

Currently the car has open long tube headers, but I will be getting full exhaust soon. The following parts are new: Fuel pump, Fuel filter, air filter, PIP sensor, both o2s, cap/rotor, plugs/wires.

Here are the codes I pulled. Where should I start?
KOEO code 22: BAP is broken
KOER Engine ID: 6cyl (WTF?? I have a 5.0.)
KOER code 33: ERG valve not opening.
KOER code 91: Left HEGO sensor reports lean (Both o2s are new. Vacuum is @ steady 16").
 
I'm Running a MAF metered engine from a 91 Mustang. The ECM code is A9L.

Before I reinstalled the EGR, I cleaned the side that faces the spacer and checked the small projection on the same side for free movement. I'm guessing the code is because of the EVP sensor?

I'm 99% sure the BAP is bad, but since I'm only at 1500ft would it effect idle that much?

UPDATE:
I checked all the plugs on the left bank and they are all a medium tan color. I compared them to the old plugs (original MC) and the old plugs are much cleaner and have almost no color.
 
The BAP isn't connected to vacuum, its open to atmosphere.

I don't think its just zero backpressure, its the fact that you can see the o2s by looking into the headers collector. They'd have to be sensing "some" of the ambient oxygen. Any input on this?
 
As long as the o2 sensors are at operating temp there should be no reading problems. I don't think you have ambiant air reverting into you exhaust.
How are you setting your idle?
Also, if the BAP is bad, it may change how the idle is set by the computer. It is not adjusting for any altitude change.
 
When I first started the car the idle was way too high, even after warm up. I checked the TB and the PO set the idle using the TP screw. It looked like he just kept turning it until the IAC was fully closed. So I backed off the TP screw until it was barley touching the little ear it sets on, then I turned it in 5 turns. Then I reset my TPS to .94V, and cleared the KAM.


What really gets me, its that my code scanner reports a 6 cylinder.
 
For some reason I can't remember what a PO is.
Anyway, here is how I set my idle.
Start the car, then unplug the IAB.
Turn the idle set screw until the car will idle around 7-800rpm's with the engine at operating temps.
Reset the TPS. Around .94-.98V Does not need to be exact.
Turn off the car and plug in the IAB.
Unplug the battery to reset the computer.
Plug everything back in, start the car, and let it learn idle for few minutes, then take it out on a drive.

And I'm not sure why your computer says you have a 6cyl car.
 
PO= Previous Owner

OK I did what proxses said and the idle has smoothed out some, although it seems to idle a little fast, and it still surges in gear.

I just found out my alternator is bad. So Ill take this opportunity to upgrade to a 3G. Then I'll drive down to the exhaust shop and get my mufflers put on.
Hopefully without getting a noise ticket.