2004 XC90 MAF, Rich Off Idle & Misfire

[Politikz]

2004 Volvo XC90 T6 (SUV 2.9L twin turbo).

First symptom, ECU reports #2 bank rich off idle. About 4 weeks.
Second symptom, engine stalls & rough idle - ECU reports #2 and #1 bank rich off idle.

Inspection found vacuum line disconnected from intake shortly after mass air flow (MAF) location (I still cant figure out what the hose goes to). New hose cut & line reconnected.

New symptom - ECU reports MAF failure, higher voltage than expected.

New MAF located and installed, no change in symptoms so old MAF reinstalled. Further inspection found upper intercooler hose deteriorating, hose replaced.

New symptom during test drive - about 2 miles to gas station. Drove to gas station & added 5 gallons (it was almost at redline) ... turbos were working & things seemed good except low idle rpm (600). After filling, started vehicle o.k., but shortly after engaging transmission, engine died & ran rough.

Limped home & ECU reported previous errors plus misfire in cylinders 1, 2, & 3 (see picture).

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Current suspects are:
- Bad battery (have noticed more drain than what should be normal, but it's been starting ok)
- Bad O2 sensor
- Bad TPS
- Bad catalytic converter

Anyone with a solid lead would be greatly appreciated!

[JDS60R]

What MAF did you buy for replacement? OE or OE manufacturer seem to be without issue in other threads while non OE seems to cause issues.

[Politikz]

MAF was refurbished from O'Reilly (Kragen).

[Stravlr]

I would clear the codes and see if they come back. The misfires might be because of the low fuel - you could have sucked up some crap. If the MAF re-appears it might be a bad rebuild. (IMO) stick with new bosch for these items.

The rich off idle might be from loose intake piping. check (and recheck) everything from the MAF to the turbo thru the intercooler to the intake. I'd bet you find a leak.