I have finally got a code to appear on the ses light. the car is a 91 that was converted from tbi to a 92 tpi a few years ago. recently I have been having running issues. it starts and idles fine, when you get it in the 2k-2500 rpm range it sputters and pops in the plenum. it feels like its losing power when driving.
fuel pressure is at about 40 with new injectors, fuel filter and afpr opened all the way. ive switched out everything and tested the tps and iac.

i had been driving the car a lot over the last few weeks and finally got a code 44.

lean o2. the wire looks good so any ideas?

 

As a matter of course, the O2 sensor should be changed around every 30K (IIRC).

Might want to pull a few plugs and see what they look like...if sooty, then definitely O2 sensor.