Hi everyone! Been struggling with emissions codes and hoping that y'all might help with a final solution. Currently cannot register the car here in GA until I solve so any suggestions are greatly appreciated.

Details below:

• 05 3.0 Estate with 120k Miles
• Off the road for over a year so a fair amount of service was needed
  • 6 new Bosch plugs
  • new O rings for VVT
  • new upper and lower intake manifold gaskets
  • new o rings for intake vacuum (brake booster and PVC)
  • new vacuum lines for fuel pressure sensor
  • new clamps for the bellows between the air box and intake
  • 4x new O2 sensors (Denso downstream and Bosch upstream) These were replaced to correct the original P0174 code that started this mess.
• Car has been smoke tested with a pro machine to eliminate any other vacuum leaks or mis-adjusted parts
• I have read the codes with both my OBD2 and the parts store reader and am getting the same info from both.

Currently I am fighting a couple of issues that may be relevant:

• 2 codes: p1000 since it won't pass readiness and the P2A01 for the O2 senor.
  • I had all new Bosch units but replaced the downstream with the Denso's hoping it would solve.
• A slightly surging idle (650 to 750) at cold start and then again at operating temps (not sure if that is a separate issue or relevant to the problem). Chasing vacuum leaks hasn't solved it.
• Super fuel rich exhaust at start-up
• Light throttle and the car runs just as it should, part throttle or further and she bucks and surges.

Any and all suggestions are welcome, at this point setting it on fire is also on the table...

 

upstream air fuels should've been replaced with denso

p2a01 is basically the global obd version of the p2096-2099, it's not telling which way "secondary" fuel trims are bad. got exhaust leaks? how are primary trims

 

xalty, thanks! really appreciate the assist on this.

Understood on the upstream sensors being Denso as I assuming that they are also acting as widebands? Therefore more specfic data comes off of them? I went off what the code was saying which is why I swapped what I believed was Sensor 2.

Also just to confirm before I swap anything else out, the ones marked in blue on the drawing are "downstream", correct?





Also I took the car out today and did 120 miles or so of mountain and city running to try and confirm what data I was getting back from OBD2:

Details are below:

Double checked under the car for any exhaust leaks; no obvious ones with it on ramps or while poking my head around the center section.

• Long Term Fuel Trims (bank 1-2): 0.0 (these stayed rock steady the entire trip)
  • My understanding is that these shouldn't move much at all, correct?
• Short term fuel trims (bank 1-2) (idle): varied between high of +10 down to -13
• Short term fuel trims (bank 1-2) (2500-3K rpm): varied between high of +22 down to -18
• Bank 1 Fuel trims: steady at 0.78 with very slight variation down to -1.56
• Bank 2 fuel trims: fluctuating a little more between 0.78 and -1.56

car came up to temp (185-206 deg) just like normal, AFR stayed between 13 and 18 most of the time and it did indicate that it did switch from open to closed loop on my reader.

Thoughts?

 

now look for your downstream fuel trims. should say fuel trim bank 1\2 sensor 2

 

xalty, the data I am getting from the monitor labeled fuel trim bank 1/2 sensor 2 is running between +0.78 and -1.56 mostly holding at 0.00 for seconds at a time.