I has been over a week and 2 fill ups since I installed the Bosch Platinum spark plugs, and my gas mileage stayed about the same but my idle is phenomonal! Love when I have to look at the dash to make sure the engine is on.
In all fairness, I cleaned my throttle body before I installed the Bosch's...... I also cleaned it before I installed the NGK's and never got that smooth idle. go figure!
All types of ignition system have a common goal .... to provide a spark for combustion. How efficient it is doen depends on the spark plug.
2008 Sport Liberty
Cold air intake*Trush (magnaflow) turbo muffler* Hypertech power program*
Hood Prop mod. Battery Quick Release mod.
Resonator removed (sounds like a V8 on start up)