The $12 junkyard intake tube that made me stop believing in "gains" forums
I grabbed a factory air box off a wrecked V6 at Pick Your Part in Sun Valley for $9, and spent another $3 on a new filter, mostly just to fix a cracked intake boot. Ran it for a week and my butt dyno felt nothing, but my highway mpgs went from 24.1 to 26.3 on the same 40 mile commute I do every day. Turns out the old box had a mouse nest the size of a softball choking it off, so the "upgrade" was really just making the car work right again. Anybody else get fooled into thinking a part helped when you were just fixing something dumb?