02 Maxima trouble codes! Please help!

[blasphemy101]

Over the weekend, I made about a 45 min. highway drive down to a friend's house. On the way back, my check engine light came on. I stopped by autozone today, and they pulled 4 codes for me:

p0011p0021p1147p0139

I know the scecond two are for the bank 1 sensor 2 o2 sensor. That's an easy fix, and I was expecting a sensor to go soon anyways (a little over 55k on the odometer), and I have no problem doing the job myself. The other two bother me quite a bit more, however. Here's what the reader told me they mean:

p0011: Intake Valve timing (IVT) control circuit failure - bank 1p0021: Intake Valve timing (IVT) control circuit failure - bank 2

Probable cause: IVT control solenoid open or shorted; cam/crank sensors out of phase; dirt buildup at controll valve.

I think it's curious that the same code came up for both sensors though. So is this just a matter of the bad o2 sensor causing errors with other aspects of engine management, or am I looking at other repairs aswell? Whatever the case, does anyone know what could be going on here? The guy at autozone told me I was looking at a lot of work and I should just take it into a shop and have them fix it, so I'm assuming it's a difficult job and the labor costs are going to be stupid high.

EDIT: So far, I've gathered I should at least change the oil and filter and replace the bad o2 sensor.
Modified by blasphemy101 at 2:17 PM 1/11/2010