What is this ??

I think they are a resistor in a box that you splice into your temp sensor, or one of the sensor, to lower it's output to make the engine think it should be pumping in more gas, i.e. makes the mixture richer and supposedly gives you more power. Just a guess based on other things I've read.

----------------- Jim '88 LX 5.0 (now in car heaven) '89 LX 5.0 vert '99 GT 35th Anniversery Edition - Silver Mods to date - Relocated trunk release to drivers side, shortened throttle cable.

Not sure. It may not drop the voltage that much as on some vehicles that would set the check engine light if it stayed in OL too long. I think it mainly just trys to fool the computer into running a little rich since most pollution controls push to the lean side normally.

----------------- Jim '88 LX 5.0 (now in car heaven) '89 LX 5.0 vert '99 GT 35th Anniversery Edition - Silver Mods to date - Relocated trunk release to drivers side, shortened throttle cable.

Its a POS (Pretty Obvious Stupidity)...

Any of those 30$ scams will only try to fool your computer into staying in open loop which is not a performance setting but a warm-up or limp mode strategy...

Just 2 cents

Serge

I think it's a load of sheep dip.