JayEmCee

I've been trying to diagnose this code for a couple of weeks now. P2A00 is bank 1 sensor 1 O2 sensor. I've tried replacing the sensor, clearing the code, running the idle air relearn procedure, and it comes back while driving around to ready the ECU after the resetting the idle air relearn. I also tried cleaning the MAF sensor without effect.

My OBD2 scan tool pulls freeze frame data:
Fuel Sys 1: CL
Fuel Sys 2: CL
Calc Load: 30.5%
ECT: 199.4
STFT B1: 23.4%
LTFT B1: 0%
STFT B2: 10.2%
LTFT B2: 0%
Eng RPM: 1325
Veh Speed (MPH): 36
TPS: 5.1%

I've had the car since October, and it's been in the shop since October, just got it back a couple weeks ago. The engine was replaced, and the headache I've gone through to finish what the shop the warranty company sent my car to (which drained my extended warranty to zero), is insane.

I noticed after I had replaced the B1 O2 sensor, that they didn't tighten the clamp around the intake manifold, so air was going directly in bypassing the filter/MAF partially. Closing that didn't help either, and the freeze frame data above is after I tightened the clamp.

Any help would be greatly appreciated.

JayEmCee

So, I got an ELM327 and Torque App. I made some graphs.

You can see that B1S1 is reporting a constant voltage lower than S2 and a higher STFT. Is it likley that the sensor bung has screwed up threads? The engine in the car is a replacment installed under (now depleted) warrenty.

I had a pro check for leaks, and he said he could find none.