I have 2001 (07/'01) V40.

Today I got it back from my new mechanic (first time using him).

He said the VVT Hub had locked up, ruining the serpentine belt.
(I'm very ignorant, so forgive me if I'm quoting him wrong)

Here is a list of things he replaced:
-Coolant
-Camshaft seal
-Camshaft seal
-Serpentine belt
-Hub
-Oil Filter
-Oil


Driving it home I noticed that it just didn't feel right. Then the check engine light came on. I took it to Advance Auto to have the codes read. It kicked back 6 codes.

-P0172 Bank 1 (system too rich)
-P0171 Bank 1 (system too lean)
-P0301 Cylinder 1 misfire
-P0302 Cylinder 2 misfire
-P0303 Cylinder 3 misfire
-P0304 Cylinder 4 misfire

If anyone out there knows of any one thing that could have cause these symptoms that may have come off and not been properly reinstalled during this fix, PLEASE help me out. It was an expensive job and I don't want to spend more money than necessary.

Thanks, FW