Yeah, @wesley139, that paperclip trick is a lifesaver for sure.

Man, that's the worst. Those generic P-codes are useless, you need the manufacturer specific stuff. I learned that the hard way on a Chevy with a weird misfire. My old Autel would just say "random misfire," but a buddy's better scanner pulled the exact cylinder and showed the injector waveform was dead. Saved me from swapping coils for nothing. Don't cheap out on the main tool, it costs you more in labor.

Paper airplanes are a legit test of aerodynamics though. That's basically applied engineering.