Whats the differance between this button? Wats the benefit of it being in power mode. I heard the the gas mileage isnt the same...plz help me understand this button.

 

transmission and throttle response differences, shouldn't not be a huge difference in mileage as the engine maps aren't altered.

in a nutshell:
normal mode=self-evident
power mode=sharper throttle response, transmission is more willing to downshift and will hold gears to the redline
snow mode=dampened throttle response, trans will start from 2nd gear instead of first and tend to hold a higher gear than usual to maintain traction in snow.

 

Oh ok makes sense, thanks PD. I took the intake cover off once and then took tsc off and put it pwr mode and as I was rollin I punch it and was gone.
Another day when it was raining I did the samething except sitting still pwr braked it and my boi said both rear tires were spinning. Does this car have Positive traction?

 

no, but if you look in the sticky you'll see a discussion on a possible LSD-like effect due to wear in the diff. no LS400 ever left the factory with a limited slip diff.

 

Power mode = more fun.

On 98-00 models, does this button light up ? I think I've seen illuminated in another picture thread.

 

^yes the power/ect/snow button does stay illuminated when the headlights are on in the first or second position. it's common to see the bulb go out as mine did too when i got it. it's an easy replacement which requires removing the shifter assembly/middle console.

not exactly too sure what bulb size it is but it's either a T3 or T4 neo wedge bulb.