2003 D2 4.6 with secondary air injection

I've researched and researched and thought I've fixed this issue but I still get it.

P1171 - Banks 1 and 2 system too lean.

Here are a few items that may help solve this:

Smoke test is negative (inputted smoke removing the mass inflow sensor)
Replaced mass inflow sensor
Air filter box lid makes nice seal and O-ring is installed
Replaced Fuel Purge Valve (Bosch) and Solenoid Secondary Air Injection
Check engine light only come on at an idle. For example, I can clear the code, drive on the highway for 4 hours and the code does not come up but pull off the road and stay in idle for a few minutes in a parking lot and it will come back on.

Any thoughts or help is appreciated

 

The workshop manual lists the description of that error as....
P1171 -- System too lean (bank 1) -- Additive injector adaptive fuelling - lean limit exceeded LH bank (section 18-2-35)

On the basis that the code is only pointing to the LH bank (driver side), I would swap the front O2 sensors to see if the code also swaps to a P1174 (RH - passenger side)

 

Good thought Walt. Also, check lower and upper intake bolts for tightness. The idle only issue tells you it is a small leak because once the engine is using more air the ecu just compensates a bit for the leak.

 

So one thing I did not mention was the P1174 was a pending code as well.

I did check the bolts for the upper intake. I have the Extinct coil pack relocation kit. Some of the bolts were loose, especially the one were I lost one of the spacers when installing it last. I did find it later and held on to it.

I've reinstalled it with all 4 spacers and everything is tight. Hopefully it was this user error.