Ahh yes, 232 a lot of things can be the cause, so kind of makes it tough to figure out.

One item it could be but not likely, too high of oil level, but since it did start after a dealer oil change? Might be worth looking into.

Let's see, you have ruled out so far, MAF and air leakage, except for a intake gasket, I would assume that the smoke test would have uncovered a leaking gasket though. Your comment about it is better after warm up go against an intake leak.
How does the exhaust sound, any ticking or puffing near the exhaust manifold or where the down pipe fits.

What is the idle speed?

Fault sources:
defective MAF, air leakage, low/high fuel pressure, faulty sensor signals, leaking injection valves, contaminated oil, too high of oil level, leaking EVAP system.

Fault symptoms: high fuel consumption, poor performance.

I did have this code a couple of times and once it was an intake gasket, the other time it was the bolts for the intake manifold on the head would loosen after a few weeks, turns out the bolt holes needed to be repaired with inserts for full torque value.

An important maintenance items is cleaning and tightening the connections under the hood. Inspect every wire for worn insulation, especially those that are near the engine block, on top and along the side. Clean the coolant connector at the rear of the head, a bear to get at. Clean all of the ground points too, near the battery, the one on the driver side engine mount, the ones on the engine top, and I think there is a main one off the battery to the engine too.

You might have to get an ohm gauge and test for continuity from the sensor connector all the way to the ecu. Check the big plug on the wheel hump for oxidation.

DanR 94 964 325,000 miles (95,000 on the new engine)

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DanR