What spark plugs?

[NORCAL_XJ]

I have an 01 XJ that am trying to get the most gas mileage I can. Right now I have the K&N FIPK and a magnaflow exhaust. I want to change the plugs cause they look like the orginals. What are my best choices. I dont know if its any different cause I have coil packs and no wires. I want to bore the stock throttle body opening right past the blade and thats about all I can think of doing. I have heard that a header for my application is useless and it seems banks is the only one to make one for that year. It has 70k on it right now so I am also think maybe a O2 sensor change. Let me know what you guys think I should do.

P.S. Right now I think I am only getting around 14-15mpg on a non lifted XJ.
I have seen people getting 20mpg out of theres.

 

[sjx40250]

I am in Oregon where we do emission test. I found out that the plugs didn't matter as much as the A/F ratio. Don't know what to suggest for your year.

 

[Dr. Dyno]

My favourite plugs for the 4.0 are the Champion copper core plugs RC12LYC.

 

[CRASH]

I have an 01 XJ that am trying to get the most gas mileage I can. Right now I have the K&N FIPK and a magnaflow exhaust. I want to change the plugs cause they look like the orginals. What are my best choices. I dont know if its any different cause I have coil packs and no wires. I want to bore the stock throttle body opening right past the blade and thats about all I can think of doing. I have heard that a header for my application is useless and it seems banks is the only one to make one for that year. It has 70k on it right now so I am also think maybe a O2 sensor change. Let me know what you guys think I should do.

P.S. Right now I think I am only getting around 14-15mpg on a non lifted XJ.
I have seen people getting 20mpg out of theres.

I have a 1999 as a DD, and we drive 100 frewway miles a day at 75-80 mph, and I get 20.2 mpg. Engine is dead stock, 3.55's and an auto. 65,000 on the ticker.

CRASH