1998 4.3L Blazer Today I put a high dollar diagnostic scanner on the obdII connection and ran a live test. It is giving feedback that the both banks are running rich. No CEL I'm not familiar with the tool so I don't know the capabilities of it and I do not have the tool info as of this time. My question is: Is is possible to tune the engine through the computer with a tool like this? May be a dumb question but I would like to know. I'll post the make and model tomorrow. I have several high end diagnostic tools available to me which I intend to learn how to use.