What are your fuel trims at idle and 1500 rpm. I also have a 96 and replaced the EGR valve because it leaks air thru the pintle.
I bought an ELM237 Wifi adapter and downloaded free OBD Car Doctor app.
Please post your best guess as to the root of the problem, if any, based on the following data.
Idle:
Bank 1 STFT oscillating about zero
Bank 2 STFT oscillating about -0.8
Bank 1 LTFT 12.5 steady
Bank 2 LTFT 12 steady
1500 rpm:
Bank 1 STFT oscillating about +1
Bank 2 STFT oscillating about -1
Bank 1 LTFT 1.6 steady
Bank 1 LTFT 1.6 steady
O2 sensor voltages
idle
O2 11 bank 1 0.14 steady
O2 11 bank 2 oscillating about zero
O2 21 bank 1 oscillating 0.16 to 0.8
O2 21 bank 2 oscillating about -4
1500 rpm
O2 11 bank 1 0.3 mostly steady
O2 11 bank 2 oscillating about +1
O2 21 bank 1 oscillating about +0.4
O2 21 bank 2 oscillating about -0.8
error codes even though I replaced all the O2 sensors less than 10k miles ago:
P0133 (slow bank 1 O2 sensor)
P1131
P1132