Strange Idle When Coming Off Power 06 Verso 1.8 Petrol

[f1batz]

We just bought an 06 plate Corolla Verso, T2 with 1.8 Petrol engine, 19k miles. Everything seems find and the independent used car dealer gave it a full service and we have a 3mth warranty from the dealer (self warranted not via an insurance company).

Anyway, once the car has warmed up then when stopping in traffic the idle is a bit strange. At first, as you come to a halt, it is about 1000rpm then maybe 5 second later it drops fairly quickly to about 500rpm then stutters and brings itself up to about 750rpm and there it remains until you pull away again.

This is unlike any car I have had before, while it is not causing any real problem I am concerned it may indicate something I need to have sorted under the 3 month warranty.

Any ideas what it could be and should I be worried?

Cheers all!

Ian

[hertsnminds]

Once my Verso is warmed up the only thing that changes the idle speed is the A/C cutting in and out. Does it make a difference when the fan and heater controls at at different settings?

[f1batz]

Once my Verso is warmed up the only thing that changes the idle speed is the A/C cutting in and out. Does it make a difference when the fan and heater controls at at different settings?

I don't think it is related. The T2 has a manual dial for fan speed so this isn't changing and the strange idle is the same at every stop so unless the A/C is only coming on when I come to a halt I don't think this is related, I will turn off the A/C next time I drive it though just to check!

Thanks

Ian

[Peterkin]

Once my Verso is warmed up the only thing that changes the idle speed is the A/C cutting in and out. Does it make a difference when the fan and heater controls at at different settings?

I don't think it is related. The T2 has a manual dial for fan speed so this isn't changing and the strange idle is the same at every stop so unless the A/C is only coming on when I come to a halt I don't think this is related, I will turn off the A/C next time I drive it though just to check!

Thanks

Ian

So many of these kinds of problems go away when the ECU is reset. You can do this most easily by disconnecting the earth lead from the Battery and reconnecting it after an hour or so.

Alternatively if the problem doesn't go away you know there's something genuinely wrong. Some cars (Mazda MX-5 for instance) have an ECU bug that makes them do what you've described when you come to a halt after a fast run.