Engine stalling at idle when hot

[944fan]

Mr car is stalling at idle when it is hot. But only if I re start it. If I drive for a while till the oil gets hot, the stop the engine. When I re start if I don't rev it slightly it will cut out.

The only fault codes I am geting are P0420/P0430 which relate to catalyst efficency. I have tested the lamda probes with a scope and they seem to be working fine so I don't think the codes are related.

Any ideas? The car is a 2001 A6 2.4 V6.2

[davepoth]

Could well be a collapsed cat.

[944fan]

davepoth said:

Could well be a collapsed cat.

Interesting. Maybe worth testing the back pressure in the exhaust then?

[davepoth]

Easier to get someone behind you to watch for little bits of metal flying out of the exhaust when you rev it. Happened to my mum's Astra once.