Hi, My LQ9 in my Firebird -68 does not run as expected, First of all I get the DTC P0172 and 0175. Second, the WBO2 bounce from 12 to 18 AFR and it correspond to the short term fuel trim value that jumps between 0 and -25%. This occures when I drive at 40-80 km/h with constant TP. I have moved the LH O2-sensor to the RH-side and vice versa and it did not change any thing (I thought that I should get DTC 0171&0174). The WBO2 is located after the exhaust cross-over. Look att the screen dump from EFIlive.

 

how many miles on the O2'S ? try running in open loope and set the commanded AFR to 1.0 then check your AFR readings.if it is richer than 13-13.5 then you have something wrong going on.

 

The engine is from 2002, I bought i 1 year ago. I think it have 31k miles.

 

ok try what i told you to do.run the car in open loope and set the commanded to 1.0 then check your A/F readings.