EFIDynoTuning Forum

Hope this is the right place to post this. I've been having some issues with my O2 readings on an 04 GT. The passenger side O2 likes to camp out around 0.0v and fluctuates just enough to not cause an O2 stuck lean error code. The driver's side O2 is a lot more lively and tends to move between 0.2-0.58v. Neither of the O2 sensors ever read above 0.58v, even at WOT. I've also verified that the passenger side of the motor is leaner than the driver's side via a wideband.

At this point I've done the following:
- Checked both O2 sensors signal, ground, and heater wiring for continuity
- Replaced the O2 sensors with new NGK units
- Fixed an exhaust leak between the header and midpipe
- Smoked the motor and fixed a small leak at the TPS
- Checked all vacuum lines for leaks and replaced PCV unit

I am at a loss how to proceed getting the O2s to switch properly. The motor is a 4.6l with a Vortech supercharger in a draw-through MAF configuration and has a BBK 78mm TB. The EGR system has been deleted with a block off plate at the TB and a plug at the exhaust manifold.