Gearbox (?) question

mrfunex · April 10, 2016

So this came up on another forum and I wanted to know if it's normal gearbox behaviour...

Picture this, going along a 40mph-ish road, maintaining speed, then the road starts going downhill. As you ease off the throttle to maintain speed, eventually the throttle cuts and you're getting engine braking.

Except in the ISF, you've got a lot of engine braking, so you start losing speed. As I come back on the throttle, there's a small but noticeable bit of driveline shunt as the fuel starts flowing again. There are a few roads round here where I feel I'm coming on and off the throttle all the way, which is noticeable. Being an electronic throttle, there is a detectable switch between overrun and v light throttle that can't be smoothed out by even more delicate pedal control.

My question is, does anyone else have this or am I the only one?

MNMJ · April 11, 2016

I didn't notice anything like that in 36,000 miles. I would go out and try to replicate it out of curiosity, but the IS-F is gone

Toothy · April 11, 2016

Does it do it in sport an snow modes? Guessing this is down to the throttle map. Could be worth investing in a throttle controller so you can program it to your preference.

Stuno1 · April 11, 2016

Only noticed the car struggling for gear a bit when driving slowly on a decline. Almost coasts for a bit before deciding on gear.

Mark G · April 11, 2016

Yes, mine does the same thing as Stuarts, takes a second to decide which gear it wants.

mrfunex · April 11, 2016

Seems to happen in all modes, I'm wondering whether the throttle body needs a quick clean, or perhaps a bush somewhere is a bit worn. Better get my toolkit out!