Today I installed a new O2 and CTS, and my car is still running slightly rich. The exhaust has a strong gas smell, and my BLM's are 123-125 at idle. Before changing the O2 sensor, the ECM was getting a false lean, and BLM's were at 158. Now, I get no SES light, and no error codes. Using WinALDL, I can see that the ECM seems to be fighting to try and adjust the fuel mix - one second the O2 will read lean, the next it will read rich, with the ECM constantly trying to compensate. The only thing left that I can think of would be bad injectors. They all tested right around 16.7 ohms, and I've confirmed that they hold pressure, after the pump is off. I put a long screwdriver on each one and listened to them with the engine running, and it almost seems like some are louder than others, but it could just be my imagination. Any ideas?

 

what is your fuel preasure

how did you check the injectors for leakage

did you take the upper pleneum and runners off then lifted up the fuel rail with a towel underneath and turn the key and let the fuel pump prime

if not take it apart and check

 

Fuel pressure is about 43psi, with the key forward and the engine off. It holds pressure after the fuel pump is off, so I don't think the injectors are leaking anywhere.