What rare these things I see on e-bay, for $10.00 that promise 25HP,
and +10 MPG. Must be a scam.

They don't work. If they did I'd have one now :D

This pops up from time to time -

What they do is sell you a resistor that you replace you IAT (intake air temperature) sensor with. It attempts to 'fool' the PCM in thinking it's cold outside, therefore adding more fuel. In reality, the car learns to ignore the sensor and often throws a CEL light.

By in the day long before the sophicated PCMs, removing the IAT sensor and place it in the fridge, after a couple of hours measure the resistance and then using a resistor of that value would be the simple way of over-fueling - not now.

Garbage.

if only it was that easy

I have a brass magnet, a board stretcher, and a bridge in Brooklyn for sale on ebay too. Wanna buy?

It Only Works If You Put The Sticker On The Side Of Your Front Fender After U Install It. Duh

Thanks guys, those were fun replys. I'll just pray for lower oil prices, will probably work better.