[95wtlb]

My truck seems to idle and run not quite right. I called Express Oil Change and they said they have a machine that connects to the GM1 whatever and reads o2 sensor, etc. He said whatever the problem is that he can diagnose it. Is anyone familiar with their service and what it does? And if it's worth paying for? I heard that on my 95 I could read the codes with a paper clip somehow. Could I do the same thing they're charging $75 for?