My infinty g35 has a code p1168 - 2005 Infiniti G35

It's usually located within the centre console alongside the shifting knob. You'll have to remove the skirt around the shifter or remove the plastic cowling around it to gain access.
It's normally a temporary switch that is a plunger or detent style.
Good luck!

check "U" joints for wear or dry

cooling fans as interior climate control thermostat failure

or engine bay ....aircon or motor cooling fans

Try to clean the throttle body using carburator cleaner.

yes....87 is perfectly fine and should be used all of the time with confidence. The higher octane fuels can sometimes help with a knocking engine but are mostly used for higher end vehicles.

post catalyst fuel trim system correction valve above threshold (bank 1) N62 Engine (4.6/4.8)

Problem with the O2 sensor bank 2.
You'll probably need a book and a scanner for this.

its on the rear(firewall side) of the cilinder heads.100% sure

NISSAN OBDII DTC

P1105 Manifold Absolute Pressure/Barometric Pressure Switch Solenoid Circuit

P1110 Intake Valve Timing Control Circuit (Bank 1)

P1120 Secondary Throttle Position Sensor Circuit

P1125 Tandem Throttle Position Sensor Circuit

P1132 Intake Valve Timing Control Position Sensor (Bank 1)

P1135 Intake Valve Timing Control Circuit (Bank 2)

P1137 Intake Valve Timing Control Position Sensor (Bank 2)

P1140 Intake Valve Timing Control Position Sensor (Bank 1)

P1145 Intake Valve Timing Control Position Sensor (Bank 2)

P1148 Closed Loop Fault Detected (Bank 1)

P1168 Closed Loop Fault Detected (Bank 2)

P1210 Traction Control System Signal Fault

P1220 Fuel Pump Control Module Fault

P1320 Ignition Control Signal Fault

P1335 Crankshaft Position Sensor Circuit

P1336 Crankshaft Position Sensor circuit

P1400 EGR/EVAP Control Solenoid Circuit

P1401 EGR Temperature Sensor Circuit

P1402 EGR System Fault Detected

P1440 EVAP Canister System Leak Detected

P1441 EVAP Vacuum Cut Valve Bypass Valve Circuit

P1443 EVAP Canister Control Vacuum Switch Circuit

P1444 EVAP Canister Purge Volume Control Valve Circuit

P1445 EVAP Purge Volume Control Valve

P1446 EVAP Canister Vent Valve Circuit

P1447 EVAP Canister Purge Flow/Volume Control Valve Circuit

P1448 EVAP Vent Control Valve Circuit

P1490 EVAP Vent Control Valve/Bypass Valve Circuit

P1491 EVAP Vacuum Cut Valve/Bypass Valve Circuit

P1492 EVAP Canister Purge Control Valve/Solenoid Valve

P1605 Transmission Control Module A/T Diagnosis Communication Line Fault

P1705 Throttle Position Switch Circuit

P1706 Park Neutral Position Switch Circuit

P1760 Overrun Clutch Solenoid Valve Circuit
P1900 Cooling Fan Control Circuit
sorry but your code reader is not reading manufacturers codes ,if an american market vehicle then you should be able to read them but if this is a europeon model then how did you manage to get this code??

P0235....Turbo/Super Charger Boost Sensor 'A' Circuit

this is a generic code if its any help