I've searched high and low and can't find a reasonably priced kit to scan my 1990 lesabre. I have a good laptop that would work fine (w/ a serial port). I need decent software that will read codes, tweak, display RPM, speed, etc. Also, the hard part for me is finding the right cable connection: is this OBD I or II? I think it is not II b/c of the age of the vehicle. I can't seem to find much info on this. Can anyone suggest a solution?

Its OBD I

I have used software from this site on my 87 lesabre and 93 S=10. You have to fabricate a cable.

http://web.telia.com/~u60113744/software/winaldl/winaldl.htm