Lean and rich at the same time? I can believe rich because my 2.5 is probably averaging 8mpg rather than a best of about 15. I performed an ignition service, installed new NTK oxygen sensors, replaced the manifold gasket, and went through the vacuum system. The fuel tank is clean, the pump is a recent replacement from Carter, at least that's what the box said, and both fuel and air filters are recent as well. The converter is the free flowing type now, and everything seems to be in order, but still I get terrible fuel economy despite being perfectly reliable to drive.

I've had maybe six months without a check engine light and never had better fuel economy than a 4.0, just with half the power. Bonus code today is a P0133, slow response, O2 sensor circuit, bank 1 sensor 1. Probably packed with carbon.

It leaves a nice black spot in the driveway on cold starts where the tailpipe points towards the ground.

I have a Snap On Solus but I'm always learning more about how to use it.

I'm not interested in spending much on it, just waiting for a 4.0 donor to come along for the right price, but it would be nice to make it run right in the meantime. It is a zippy little engine to the top of second gear. If I can be pointed in the right direction to understand better with the scan tool, I'd sure appreciate it.

Otherwise, I can only offer a sense of pride in answering something the Jeep forums could not.