Engine Cuts Out when Slowing/Coming to Stop

[RJS1995]

Currently running 306 XS with 406 SRI 2.0 Turbo engine

When slowing down for roundabouts/junctions you will usually get a judder when it is about to do it, then when down the revs they bounce up and down as if about to cut out then engine cuts! Usually the engine will start again but getting beyond it now, need some advice.
The speedo also isn't working don't know if that affects it but it hasn't been working for some time now and hasn't seemed to affect it previously.

Thanks in Advance folks!

[mjb]

People pay a lot of money for that in new cars

First thing I'd suggest is to give the ICV (idle control valve) a clean with carb cleaner. Pull the ICV intake pipe off too, and give it a good cleaning. Also see if cleaning the throttle pot (bottom connector on the right iirc) helps. Make sure the connectors are clean too. Try replacing the speed sensor - it's a creamish plastic unit on top of the gearbox right next to where the driver's side driveshaft goes in.

When the engine becomes hard to start, does holding the throttle pedal help?

[Ares]

I had similar problem but it was due to LPG system.
While i was driving on petrol,everything was ok,but if i switched to LPG car was doing the same thing as yours.
Coming to some junction the rev would go down,high up and shut down after it.

[RJS1995]

When the engine becomes hard to start, does holding the throttle pedal help?

Yeah usually when starting have to give throttle

[mjb]

When the engine becomes hard to start, does holding the throttle pedal help?

Yeah usually when starting have to give throttle

In that case your problem is with the idle air supply.

It's almost certain the fault is with the ICV, throttle pot, or wiring to those. Get cans of carb cleaner and electrical contact cleaner (always useful to have anyway) and start cleaning