MPG for a 4cyl?.....For a 6cyl?.....

I have a 97 Wrangler SE with 97k on it and i get 17 mpg. The tires are P245/70R15. Is this normal mileage? I was wondering if since there are so many hilly roads all over this town would i get better mileage with a 6cyl because i wouldnt have to floor it to get up them. As far as I know the car was tuned up recently too.

I found the problem......the O2 sensor is bad.

I found the problem......the O2 sensor is bad.
Yikes! I just figured my mileage last week, and it too is 17! (4.0 6-cyc) I guess I need to replace the same o2 sensor. Is it the one on the cat converter? What is/should be your mileage now?

Yeah, it is the one on the cat converter. If you have a 6 cyl you should be getting around 18 mpg. The only reason i was worried is because i have a 4 cyl which means it should be a little more economical. It turns out that it was more than just the 02 sensor though. we took it into the shop to get something else fixed and the mechanic recommended switching out the distributor cap, rotor, wires and plugs. Apparently jeeps dont like Bosch plugs or wires, and according to the mechanic that can significantly affect the mileage.

I forgot to mention......the manual suggests replacing the 02 sensor every 82,500 miles

So what is your mileage now? My 97 got 17 everywhere also (even in 4lo on the beach).

2002 6cyl, 23mpg highway
2004 4 cyl, 22 mpg highway and climbing (only 8k miles so far)

Oh yeah, and 97 had 235/70's. '
02 225/75, and '04 has doughnuts- 215/75 - hey they were free.

Its hard to tell what my mileage is, I think the speedo is off because of the tires. If thats the case I figured that the odometer has to be off too. Going off of what the odometer has been saying though I figured my mileage to be 17 mpg city.