00 xj MPG?
ok so i slap on some new to me bfg m/t's last weekend, nothing big there just 235's also changed out the orginal plugs as the jeep has 110k on her now... also put in a K&N air filter at this time. went to the local autozone to have the check engine light checked and found out it was a for the fuel cap.. not being on tight enough but it is and the seal is good.. but if i leave it idle for more then 5-10 minutes you can smell fuel a little bit... always been that way since I got it 1 1/2 years ago. anyways since this my last two tanks I have only been getting about 230-240ish miles to the tank normally i get around 280-300. so why would new plugs and new air filter get me worse milage the tires are the same size just m/t instead of the street tires it had. I am wondering if I gapped them wrong as the old plugs when takin out were very worn out platinums with a huge gap.. I put in some champion plugs non plat.. would that really make that big a difference? thanks