Variable 10k mod = nothing

Today tried the 10k mod and found it didnt do anything for me. I put a 6.2k inline with a variable 10k resistor, then dialed it into a total of 10k. I then plugged it in and flipped the switch and nothing happed. The idle didnt change, no power difference. I varied the resistance all the way from 6.2 to 16.2 and found no difference at either setting. Removed that bit and installed a straight 4.5k and it didnt seem to do anything either. I figured I would at least get the bad idle everyone talks about. I checked my wires that went into the ipr and each had voltage on them (@12volts) when the key was on. This tells me they were making contact. I am just puzzled by it. Everyone seems to get a noticeable differance but absolutely nota for me. I am sure I put the wires into the right holes on the IPR sensor plug.
Any ideas on the cause or cure.
Many thanks