Picked up a GTO and need some help

[Trooper182]

Just picked up a 04 GTO auto with k&n intake, pacesetter lt and SLP. Car is in good shape and got it for a good price. Only issue I am having is the cel is on and it is throwing codes P0175, P0172 and P0343. The car starts fine and drives good. I noticed a little bit of hesitation when punching it but it pulls hard. The engine was replaced right before I bought it with another LS1 with 34k miles on it. Trying to figure out where to start with clearing these codes up. Specifically the P0343 code. Thanks for your help.

[cammed goat]

If I recall, 173 and 175 could be due to an external air leak. CHECK YOUR K&N INTAKE!! I've had mine come off at the throttle body and the CEL comes on. Check ALL clamps and couplers. As for the P0343, before you start taking things apart, check the wiring under the hood. Do you know if the engine has been powerwashed prior to you buying the car? Check your wire connections and have your battery tested. For the slight hesitation, get some CRC Mass Airflow Sensor Cleaner and clean your MAF. Clear all codes and drive to see if the light comes back on.

Give a holler if you need anything else.

[liemmayer]

yes, this is a very rare model and really cool, a whole legend and classic!