Reduced engine power, codes P0108 and P0641

Going by codes i looked up how to test MAP sensor/voltages but have not done so yet.

Yes. If these are the codes then the MAP sensor is most likely giving the PCM incorrect info which leads to the engine having low power due to the air fuel mixture not being correct.

Here is a guide that helps with this:

https://www.2carpros.com/articles/symptoms-of-low-engine-power

However, I am attaching the testing below for both codes but the P0641 is just telling you that the 5 volt reference from the PCM is not correct. This is most likely due to a sensor that is sorted to ground.

So the fact that you have a MAP sensor code as well, most likely the MAP sensor 5 volt supply is shorted to the ground terminal in the sensor.

Please run through this testing and let us know what questions you have.

Thanks