CEL after STILLEN G3 intakes, headers, exhaust and BERK HFC install
 

I recently had my STILLEN headers, exhaust and Berk HFC installed and have been getting a CEL light. I had the CEL scanned and I got the ff codes initially:
P0113 (Intake Air temperature Sensor 1 Circuit High)
P0031 (HO2S Heater Control Low Bank 1 Sensor 1)
P0051 (HO2S Heater Control Low Bank 2 Sensor 1).

The mechanic then reset it and we got these codes after:
P1148 (Closed Loop Fault Detected Bank 1)
P1168 (Closed Loop Fault Detected Bank 2)

I called Stillen and asked if they knew what it could be. I was told to try to disconnect the battery for 10 mins and see what happens. I did, and got the same thing. FYI, I remember that the mechanic did NOT disconnect the battery during the entire install. And my stock intake boxes were also disconnected because the install of my Stillen G3's could not be completed since I got the wrong parts.

So my questions are:
1. Do I need to replace any parts? (sensors, etc.)
2. Which parts are defective?
3. What do I need to do step-by-step to resolve this issue?

PLEASE HELP! I need to get this resolved soon since I dont have any other means to get to work! Any help will be VERY MUCH appreciated. TIA! :tiphat:

go to an autozone or the likes and ask them to check and clear it.

I did. They cleared it and the first 3 codes (P0113, P0031, P0051) were replaced with 2 new ones (P1148, P1168)...

Maybe this?

The closed loop control has the one trip detection logic.
Malfunction is detected when the closed loop control function for
right bank does not operate even when vehicle is driving in the
specified condition, the closed loop control function for left bank
does not operate even when vehicle is driving in the specified
condition.

POSSIBLE CAUSES

The front heated oxygen sensor circuit is open or shorted.
Front heated oxygen sensor
Front heated oxygen sensor heater

ALSO

On Board Diagnosis Logic

To judge the malfunction of front heated oxygen sensor, this diagnosis
measures response time of front heated oxygen sensor signal.
The time is compensated by engine operating (speed and
load), fuel feedback control constant, and front heated oxygen sensor
temperature index. Judgment is based on whether the compensated
time (front heated oxygen sensor cycling time index) is inordinately
long or not.
Malfunction is detected when the response of the voltage signal
from the sensor takes more than the specified time.
POSSIBLE CAUSE

Harness or connectors (The sensor circuit is open or shorted.)
Front heated oxygen sensor
Front heated oxygen sensor heater
Fuel pressure
Injectors
Intake air leaks
Exhaust gas leaks
PCV valve
Mass air flow sensor (Image is of an Xterra Sensor)

wait im sorry is the write-up talking about the o2 sensors on the HFC's or the headers?

I dont know aI just saw this on the web and copied it for you. Since you were doing the intakes maybe the MAFs need to be cleaned good and make sure they are in right, even tho I doubt they can be put in backwards.