My wife has an old F reg Passat that when it starts from cold it wont 
idle properly.  The revs are up and down between 500 and 2000 and dont 
settle down until the engine is warm.  It cuts out and splutters until 
that point is reached.  Car has the RP 1800cc engine with what looks 
like a Mono-jetronic system.

I pulled the wiring plug from the socket and the revs increased like 
they should.

Anyone know what the likely problem is or how to diagnose it ?

Thanks

john

"JohnB"  wrote in message 
news:3i7v04FkallaU1@individual.net...

> My wife has an old F reg Passat that when it starts from cold it wont idle 
> properly.  The revs are up and down between 500 and 2000 and dont settle 
> down until the engine is warm.  It cuts out and splutters until that point 
> is reached.  Car has the RP 1800cc engine with what looks like a 
> Mono-jetronic system.
>
> I pulled the wiring plug from the socket and the revs increased like they 
> should.
>
> Anyone know what the likely problem is or how to diagnose it ?
>
> Thanks
>
> john


first, check for air leaks.

mrcheerful

On Sun, 26 Jun 2005 16:12:10 +0100, JohnB
 wrote:


>My wife has an old F reg Passat that when it starts from cold it wont 
>idle properly.  The revs are up and down between 500 and 2000 and dont 
>settle down until the engine is warm.  It cuts out and splutters until 
>that point is reached.  Car has the RP 1800cc engine with what looks 
>like a Mono-jetronic system.
>
>I pulled the wiring plug from the socket and the revs increased like 
>they should.
>
>Anyone know what the likely problem is or how to diagnose it ?


These central point injection systems can be a bugger to diagnose.
It could be as simple as one of the (several) temperature sensors
playing up.  My brother-in-law had the same year car and a similar
problem.  He never did get to the bottom of it.