Ok I have been trying to get my aldl cable to work with tunerpro and winALDL for some time but it worked intermitently and I was getting frustrated to say the least! I have found the cause and I hope that it will make others aware of this and save them time and frustration. I use an old laptop that has a used battery so I plugged it in a 400w inverter to get it running. it so happens that if the power drawn from the inverter was draining power from the ecm and it was screwing up the signal! I own a 1989 ke tbi blazer so the lighter plug must be a bit corroded and is creating resistance therefore drawing to much power away. I noticed it while driving my factory voltmeter was going down a bit and the digital gauge on the inverter was showing between 11.8-12.1v so I figured I would try an independant source from the dash power and voilą! perfect signal! hope this helps.

Mat