I just got these codes...P0491 and P0492...I'm wondering how vital it is that I repair these...don't have much time at the moment...will it be okay for a few days? X seems to run fine. Also how difficult is it to replace these parts, any special tools?

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2010 BMW X5 ///M
Silverstone Metallic
Black/Black Merino with Black Piano Trim
Premium Sound
Driver Assistance
Comfort Access
High Gloss Roof Rails

Gone but not forgotten: Upgraded!
2003 BMW X5 3.0i
Titanium Silver
Navigation
Cold Weather Package
Premium Package
Heated Steering Wheel
20" wheels (275/45/R20 all around)
Supersprint Magnum Exhaust
AFE Cold Air Intake
Bimmian Chrome Guage Rings
What's A Resonator?