What exactly is a resitor mod?

 

You put a resistor in the icp sensor i believe and it will raise icp. If you have a chip it already does this so there is no point

 

Which resistor mod?

As stated above, there is one for the injection control pressure sensor which will mimic products like the Edge Juice, Dr. Performance/Workhorse, and Banks 6-gun.

There is also one for the engine oil temperature sensor that causes a start of injection advance.....but that one can cause your engine to chuck a rod quite easily, especially with a programmer or chip. Don't do that one.