I don't think the blue wire (input 2) puts out any voltage, so it shouldn't mess things up that way. I would have to agree that you have proven that too little resistance to the o2 sensor signal wire reduces accuracy, but I would just keep it to 1 metering device per sensor (i.e. either an air/fuel gauge/ voltmeter/ or super afc). The afc should give the same results as the voltmeter in the same situation, but don't use both at once. there is no need. also, the air/fuel gauge is worthless compaired to a true digital read-out (acutal numbers). might as well sell it and just use the s-afc's sensor check function. The blue wire mod works great on my Stealth, and I also use input one for my knock sensor. 420A's can't do that because they use pressure sensors instead of karman vortex MAF sensors, and the readings I have obtained by using my s-afc this way has proven to be beneficial. The inputs that aren't normally used in tuning your vehicle (input 2 in this case) don't have any affect in the functions or adjustments made to your air flow readings.

Bring it on............