Has anyone come across free or reasonable diagnostic software for OBD1. I have an 89 S10 blazer, 4.3 TBI and I would like to monitor the inputs and outputs of the ECM. I can build a interface cable with the right information and use a laptop.

Thanks for any info

Do a Google search for PDA scan tool! I know they make stuff to use a PDA to read the engine data might have one for a laptop.