Runs fine until warm

Hi Mitch,

This sounds like you have a sensor issue that feeds the PCM which calculates the air fuel ratio.

I would start with pulling codes. If you have any codes then that will point us in the best direction.

Here is a guide on the most likely cause which is the air flow sensor:

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

The reason it sounds like a sensor issue is because as the vehicle warms up it is running on a predetermined set of parameters and is not looking at sensor data such as the o2 sensor. Once it get to operating temperature it goes to what is called closed loop and starts making adjustments based on sensor inputs.

Let me know if you have codes and we can go from there. Thanks

Okay, do you have the ability to monitor live data? If you do, can you tell me what the o2 sensor data is saying when it is running poorly? Including the short and long term data? Also, tell me what the MAF/MAP data is and the various temperature sensors (Ambient, Coolant, Intake) plus Baro?

Lastly, run it at idle and get those numbers and then run it at 2,500 RPM and get the same numbers. Thanks