Hey guys! I've got a 94 base model vette with an LT1 that I'm having some trouble hooking up to. Last week I got done putting her together after doing the intake, timing cover and oil pan gaskets, and fired her up to find that she was missing like crazy. I got out TunerPro and my OBD cable to hook up to her, though it took me a couple tries. I completely closed out of the .bin, .xdf, .adx and log file it had pulled up, messed with changing the ports and switching around cable configurations, restarted the computer and the program, and finally got her to hook up somehow. I got the log I needed and swapped out a couple things and got her running smoothly again, but I haven't been able to hook up a second time to see what she's saying now about fuel trim, O2 readings and spark advance/retard. When I plug in to her and hit connect (not emulate), the bar on the bottom lights up DA: Connected in blue for a second, but then the values on the data dash start jumping around randomly and it starts flashing DA: Error in red at the bottom of the screen. When not plugged in to the car, I can see the cable just fine by going into the preferences for tools and testing it there, but I can't get it to talk to the car. When not plugged in to the car but the cable plugged in to the laptop, if I hit connect, the values don't jump, it just flashes DA: Error at the bottom in red, so I know that plugging it in is at least doing something - I'm just not sure what it's doing or how to get my laptop to hook up to the computer.

Is there a certain time I'm supposed to hook up the cable to the OBD port? I.e. only at key off, key on, run, etc.? Or is there another thing I'm missing on things to do before I hook her up? Any help with this is greatly appreciated!

Thanks!
~Ken