Strange fault

[djtdjt]

Only using car at weekends, when started after 4 or 5 days runs rough for a while, stop to put fuel and will not restart until left for half hour? after that it's okay! any ideas? car is Audi 100, 1984cc. TIA.

[tonyav]

Sounds like it could be the crankshaft sensor.

[douglas9401]

bI remember years ago that the VW LT28 petrol van needed to be started in different ways when hot and cold. I seem to recall that the throttle pedal had to be pressed when starting an engine already at running temperature, no idea why but it was stated in the owner handbook.
Maybe your car has similar characteristics ignition wise.

[douglas9401]

Not bI, just I :)

[Hopkirk]

Is it due for a service?

[djtdjt]

Yes it's well overdue for a service!

[Hopkirk]

There's your answer.

At minimum it probably needs spark plugs replacing.

[TWR]

Take the car for a good Motorway blast Djtdjt, the car is bunged up with sht, what the car what's is a good clear out. tryu that before the expence of a service.