Hey everyone, new member here. Just want to say this forum has been very helpful in my efforts to get my truck running better. I'm currently trying to diagnose an issue with my 1993 Sierra SLE K1500 5.7 automatic where it idles very low in gear (~200 rpm according to tachometer) and seems to have a misfire at idle with a strong fuel smell going with it. The idle in gear will dip to almost stalling and then surge back up a bit when I'm at stoplights waiting with foot on the brake. The truck has a noticeable shake when it does this. It will do this dip/surging repeatedly until I start driving again. I bought an ALDL to USB cable and am trying to connect to the truck's computer with my Windows 10 laptop to view live data while it acts up. I have tried both WinALDL and Tunerpro software and can't get either one to talk to the truck's computer. I have my COM port for the cable set to the same as either software but not sure if there are any other things that need to be set for this to work. My ECU for the truck is Service Number: 16168625. Does the jumper in the cable need to be removed for it to communicate? I removed it and tested but no change. I'd really appreciate any tips you guys have with WinALDL or Tunerpro.