How do you get better than 12 mpg on a 1993 jeep wrangler?

Funny! 4 cyl.

Must be running like crap.. Is it? What's been done so far??

The spark plugs are new. The distributer wires are new. Most recently, the engine harness was replaced and also replaced the PCM. Had a computerized engine analysis and the report was that the CCV valve was broken. Could not find part for it.. Also said temp gadge not working. It's been through the mill it seems. Hope that helps. I'm not a mechanic so I am going with terminology from report from Firestone.

Without checking it myself... I'm out of ammo! Sorry...