On our 01 S type 3ltr is this "sport" button on the console.

OK, I basically know it is supposed to alter the shift points of the 5 speed transmission.

Today the car started this odd behaviour similar to misfiring under load from lack of fuel. We were climbing a long steady hill from the plains to the hills district. The button was in "normal" position, as we have never used it. Pushing the accelerator harder got kickdown and no more odd behaviour, mmmm. Cant be fuel, or it would not rev under kickdown.

Backed off the throttle to maintain speed, and it started mis-behaving again, so a split second decision I pushed the "sport" button, SMOOTH as ever, and felt significantly crisper.

Sooooo, does this button only change the trans mode, OR, does it also alter the fuel map. I have read many, many pages on here and elsewhere without success to this precise question.

I think we have a transmission having a moment of indecision, and the behaviour was in fact the transmission changing "up and down", very quickly, without staying in one or the other gear. A very odd feeling.

We drove the car for the rest of the day in "sport" mode, and it did feel snappier, NOT just the transmission shifts, but maybe it was just my imagination.

Any clues as to what this button alters would be good to know.

 

As far as I know - the sport button changes the transmission shift points by increasing the shift points by 250 - 300 RPM's. I would still look deeper into the drive ability issues you experienced.

Sounds like a fuel delivery problem/misfiring issue to me. (partially clogged fuel filter, failing fuel pump or transfer pump, air leak) - check fuel trims at idle and 2,500 RPM's.

 

sport button will change the transmission settings, increase shift points.....it also makes the gas pedal more sensative

 

+1, and then only when you're giving it enough pedal. I frequently turn mine on while fumbling with the GPS and aside from turning the red light on notice no difference.

 

It shifts alot different. And will hold gears a lot longer. It's also real quick to downshift vs normal mode which it takes forever.

 

Sounds like it might be misfiring and thus struggling. More revs hides it.

 

+1 Also, activating cruise control overrides the sport behavior. So, in sport mode @ say 45mph, the trans might be in 5th; activate cruise and it will automatically shift up to 6th. Release the cruise and it returns to sport and downshifts to 5th. At least that's what my '03 does.

Makes sense, as the car is more responsive in the lower gear.