Unstable reving when coming to idle

[singlecell]

TD5 Auto - So when coming to a stop when the car comes down to about 20km/h the engine seems to cut in and out a bit, starts a sort of grr grr grr as it comes to a stop then idles properly. Only does it when decelerating.
Ive seen other people online in other forums mentioning it also but I have never seen a reason for it, I have also heard other TD5s do in when then drive near me. Its always done it, and doesnt seem to be causing any issues, I am just curious what is going on.

Thanks.

[discorevy]

ecu is cutting. fueling to injectors on overrun

[singlecell]

Ah OK. So its normal or some cars are doing it wrong?

Sent from my Nexus 5 using AULRO mobile app

[discorevy]

Yep , perfectly normal , td5 s make the clatter due to the camshaft operated unit injectors , some common rail cars will shut fuelling on overrun as well but no noise because pressure on common rail is due to a pump

[singlecell]

Awesome, thanks for the info!