I've read all the emissions threads on here and I'm still stumped:

Last week I failed for high NOx so I did a boost leak test, cleaned out my EGR, cleaned out my throttle body, installed a new BISS o-ring, installed a new ISC o-ring, and fixed a leak in my IC-pipe.

First Test:
HC GPM 0.5796 - limit is 1.2000 - PASS
CO GPM 5.9712 - limit is 15.000 - PASS
NOx GPM 2.8003 - limit is 2.500 - FAIL

Today my NOx was well under the limit but my CO skyrocketed, it's like I went from slightly lean to really rich.

Second Test:

HC GPM 0.7721 - limit is 1.2000 - PASS (but higher than last week)
CO GPM 22.1448 - limit is 15.000 - FAIL
NOx GPM 2.1075 - limit is 2.500 - PASS

What would cause my CO to increase so dramatically? Here are my speculations:

1. I used throttle body cleaner liberally on my throttle body, EGR and EGR ports; could that have caused higher CO readings?

2. I filled up with gas this morning; could a full tank cause higher CO readings?

3. I removed a fitting in the line running from my wastegate to my mbc that had a bleed hole in it; the mbc is a homemade unit by the prev. owner and I'm not sure of the purpose of the bleed hole here. I removed it b/c it was leaking during the boost leak test. Could this cause high CO readings?

4. Could the ECU still be learning the fuel trims? I've only driven 25 miles since all the above mentioned work was done.

5. Longshot here - the ECU that's in the car isn't the same one that was in it last time I passed emissions. I swapped them to try and correct an IAC issue but the ECU wasn't the problem so I still have my old Eprom waiting to be swapped back in.

Any other suggestions? I've read doing an oil change helps but i passed CO last week so it has to be something that changed with the work I did over the weekend.

Info about the car: 95 turbo awd, 3" exhaust w/ flowmaster high flow cat (cat is 3 years old), stock fuel system, 14b turbo, boost set at 15psi, NO wideband, NO engine management system.

Any help would be appreciated - Thanks!