>>>*Lots of possibles why poor mileage, but I would need to see your rig. Tires affect that, gearing, loading, wind resistance, right foot, etc. But I thought you said 16-17? That's off maybe 10% from typical although I hear reports of way better. Lean/rich can affect but if she has a hot cylinder or two then mileage will suffer either way.

One gentleman even reported 28 MPG, I figure he lives on top of a big hill....gas station at the bottom... <img src="/forums/images/graemlins/smile.gif" alt="" />

Not two stages cooler on the plugs, maybe one step at most. Looks to be a little tuning issue, find it and she will sweeten right up. The plug running warm explains the ping you report, too....*EB