So I just picked up a ranger and had some questions and observations maybe some experienced ranger folks can comment on: It's a 2000 XLT, with 160k miles, 5 speed, 2.5l 1. The previous owner said it had stock 4.10 gears in the rear. Is this an option for this vehicle? 2. He threw 30x9.5/15 tires on them and I believe the stock is 225/70R15. The new 30" I think is about a 255/75R15. On a tire calculator it was calculated to be about 9.7% slower than stock. I assume this is to make the 4.10 easier on the highway? However at 65mph (actual speed 71) the RPMs turn at about 3k. Is this right? Shouldn't I be turning lower on the bigger tires? I ask this because the mud tires on there now are very loud and I want to swap them out for quieter radials and am trying to decide whether I should go back to stock or stay larger. I understand that big tires make the car more sluggish off the line but better on the highway and vise versa on smaller tires. I'm looking for people with experience and what they found to work nice. 3. I throw a "bank 1 lean" code. Any thoughts on how to tackle that would be appreciated. I can also do a search but since I am posting the above already, I thought I would ask this also. I didn't hear any vacuum leaks and I sprayed the MAF with MAF cleaner. So far that is all I have done and it has not worked. 4. Finally... on two tank fulls I have calculated mileage and although the truck seems to run smooth and idles good, I have only been getting 18mpg. I was expecting 25mpg with a 4cyl 5 speed. Do you think having 8 spark plugs or the CEL code, or the 4.10 gears or the larger tires is attributing to this? I don't drive hard on it. I shift causally at about 2.5-3k. What gas mileage is everyone else getting with a similar setup? Sucks that I have an F150 with a 4.2l getting 16-17mpg and this one is not much more.