1994 Nissan Pickup 2WD 2.4L, 155,000 miles, no EGR lift

1 owner vehicle. No repairs ever done... just routine maintenance. Suddenly won't pass smog.

Smog test as follows:

Idle: 12.0% CO2, 3.7% O2, HC @ 4 PPM, CO @ 0% -
2500 RPM: 13.0% CO2, 2.4% O2, HC @ 3 PPM, CO @ 0%

I got this info from the smog station:
Estimate to Diagnose EGR not lifting $80 + parts to start.

I found some broken vacuum lines, so I replaced all vacuum lines and surprise... still no lift.

It runs great, stalls out when I lift on the EGR at idle, so I think the EGR valve itself is ok.

Did you think it could be:
1: Cat Converter
2: O2 sensor
3: BPT
4: EGR Temp Sersor

Thanks for having such a useful site. This is my 1st post and am anxious to see what happens.