P0402 trouble code

[Gash]

I just got a check engine light and pulled a P0402 DTC. Looks like either bad EGR or DPFE sensor. I am leaning towards DPFE sensor, but not sure. Any ideas here? Also, where's a good place to order a DPFE sensor, and does anybody have a link to instructions on how to replace? Thanks.

2018 GT2.

 

[CrashBandit GT Sky]

What are the symptoms because I went to the dealership multiple times they fixed ignition coils and I replaced all spark plugs and still have a poppy and inconsistent idle. I also get limp mode sporadically which the car is almost un drivable.