Anybody know of a performance chip that actually works long term and helps highway MPGs? I've heard most of these chips only work short term until the ECU compensates for the changes.

 

Waste of money IMO...

Invest that money into a good tune up..

injector cleaner, air filter, check your tire pressures, plugs, wires, cap/rotor, and a full tank of gas and a nice dinner afterwards... is what I would do

 

haha, thanks I kinda figured it could be a waist but I figured I'd ask. Any recommendations on plugs? Its an 01 Sport with a distributless ignition. I just bought it on Friday.

 

I run NGK plugs in everything.
go to your local store and get 6 of a ngk stock number 3459

 

I too have used NGK's before the XJ, but a lot of people will recommend Champion plugs for the 4.0 I6.

 

I've heard the same thing. I never thought of Champion as a premium spark plug, but have been told that they are good in the 4.0's.

 

NGK are the best IMO