Slowing Down - Engine Reving (Auto)

A

AJZ4London

Member
Hi All

When I take my foot off the accelerator at low speeds the revs come down and go up slightly and go down, up etc. Not really noticeable but you can see it on the rev counter and slightly feel the car moving with the revs. Almost like the clutch is engaging slightly and disengaging.

Any ideas what this could be? THANKS
 
You say auto in th title but then mention clutch engaging - no clutch per se on an auto??

It's normal for autos revs to rise slightly when sat still and put into drive as it spins up the torque converter.

Difficult to comment on without feeling it, but my thought would be that the engine is going very slow, so the stall prevention picks up the revs slightly then lets them off again, creating a slight surging effect.

If it bothers you this is the stuff for dealers, indy's or an auto specialist to take a look at and adjust
 
Being new to autos myself, it does do some weird things you don't expect.

Is the problem you describe something you just noticed or it has changed recently ?
What is the range of revs going up and down when it bounces - 250, 500, 1000 revs ?
 
Sounds like the same thing my 325Ci did (mine was manual). You come to a stop, in neutral, engine gives a slight "blip" then settles. Never had any trouble with it and service adviser said it was normal.
 
You take your foot off, say 250 down the revs seem to rise and fall a couple of times before you stop. I do not think the auto is changing down, its just a couple of blips, feels like the car is accelerating slightly. I guess I'll just keep an eye.

Thanks all.
 
Hm, mine never did it but once and it was the 2.5 engine.

Keep an eye on it and mention it to your mechanic next time it's in for something routine if it doesn't get worse.
 
Not sure on that if it was while sitting in traffic its surging some Autos do this my old Calibra was awfull at the lights steering wheel would shake unless i popped her into park then it would ease a little.

My Z will get what i think is called overun (feel free to correct me ) when i lift of the Gas after acceleration where i will be coasting but the car growls and almost sounds as though i still have my foot on the pedal even better in sport mode with the odd little pop :D never looked at the revs when this happens will have a look next time.
 
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