6th Gear Cruising RPM Jumps

[Domin007]

Hi All 

Recently I have noticed that when cruising at around 60mph, in 6th gear in full auto, wen letting off the accelerator slightly, lets say when going down a hill, sometimes the revs drop a little bit when I accelerate slightly, but then go back to normal.

This doesn't really cause any issues but very rarely I can feel like the car "changes" gear, or rather engages again, I can sometimes hear the engagement. It doesn't jerk or anything though.

I know this is very vague, but perhaps someone has noticed the same thing happen to them. 

Car is on 98K - 2011 IS250

[Spacewagon52]

Do the revs kick in when the speed drops below 60? That would be normal.

On undulating roads you can can get a sort of hunting from the cruise control - throttle on then off.

[NemesisUK]

43 minutes ago, Domin007 said:

wen letting off the accelerator slightly, lets say when going down a hill, sometimes the revs drop a little bit when I accelerate slightly, but then go back to normal

Sounds normal, lift off the revs will naturally drop and then rise again when the accelerator is depressed again.

[ColinBarber]

36 minutes ago, NemesisUK said:

Sounds normal, lift off the revs will naturally drop and then rise again when the accelerator is depressed again.

It should be very minor though as the transmission should be in lock-up at that speed/gear so the rear wheels are essentially directly linked to the engine.

[Domin007]

On 8/2/2023 at 5:39 PM, ColinBarber said:

It should be very minor though as the transmission should be in lock-up at that speed/gear so the rear wheels are essentially directly linked to the engine.

Yeah its a very minor fast drop then it goes back to normal. Its that second between the gearbox engaging again I assume.