Wide band

I just installed a wide band gauge. I know alittle about it but no to much. If at an idle warm it runs 13.5. To me this sounds alittle rich and seems to have a slight stumble. If you have a stock tune with a 160 thermo will this cause a problem other then no heat. I have about 75000 on original O2 sensors should I replace them.

The stock PCM is trying to control the A/F ratio at 14.7:1 +/- 0.05 units. That's the way is swings the A/F ratio, above and below 14.7:1 to allow the catalytic converter to function. The O2 sensors and the complete closed loop control system are based on 14.7:1, so if you are not seeing that, youre system is not functioning correctly.

But... where did you located the bung for the wide-band sensor? Did you check both banks of the engine?

When i am cruisin I see 14.5 - 15.0, wide open I saw 12.0.
I have a "test pipe" and tiged it to the upper side of the test pipe-basically where the stock single cat would be

also car back fires when letting off gas and costing in gear alot!

14.5-15.0 in closed loop matches the stock programming. 12.0 at WOT (PE mode) matches the stock programming (typically 11.7:1).

it just seems rich, if i get a tune can they help. is it normal for my car to back fire when i let off in gear - i see 16.0 and it backfires seems like it's to lean to backfire and it's not a lean pop.