01' Integra - Fault Code Running Rich - Help!

Timing belt just done, possibly related?

Fault Codes:

P0170 - Fuel Trim Malfunction Bank 1
P0172 - Running Rich
First 02 sensor fluctuated between 0.1V and 0.9V
Second 02 is pretty steady at 0.8V
Long Term Fuel Trim is always in Negative Range.


Symptoms:

Vehicle shudders around 2500rpm in the lower gears.
High Fuel Consumption


Tried the following:

Cleaning IACV
New Fuel Filter
New Spark Plugs (Properly Gapped w/ New Wires)
Added Fuel Injector Cleaner
Cleaned MAP Sensor
Cleaned Intake and Throttlebody with Carb Cleaner

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Anything I might be missing here?

I would appreciate some input on which direction I should take with the troubleshooting?
-Should I investigate implications from the timing belt change?
-Do you guys think it might be a fuel system related thing ie. Fuel Pressure Regulator, Fuel Pump, etc.
-Vacuum leaks??? O2 Sensor Faulty???