I saw something similar to that on a 06 duramax. I believe it was called a Work Horse and it was a fuel pressure fooler. They claimed to get up to 100 hp smoke free hp gains just from changing the fuel pressure reading. Needless to say the truck was setting all sorts of fuel rail pressure codes and ran like crap. Took it off and wouldn't you know it ran good again. IIRC the Work Horse sold for like 300-400 dollars new.

 

Woah, so I shouldn't use that to tune my whip? ha. that sucks man, there's a lot of bs out there for uneducated people. my dad tries to buy something like this once a month. I don't know when he will learn.