2015 Yukon "System Too Rich" code, engine issues (P0172, P0175)

[dwoldring]

the ecu will start to add fuel to help cool the motor.

No, the ECU will not add fuel to cool the motor. Under high load conditions, the ECU will add fuel to cool the exhaust, but this doesn't happen at idle. Please don't spread misinformation.

 

[Tahoe14]

Hope you got an oem maf as aftermarket can be sketchy.