Volvo: V70 Second Cold Start In A Row, fuel mixture, car cold

Question
Ray,

When I start my car with a cold engine, (in order to move it in or out of the garage), it only needs to run for about 30 seconds.  I shut off the engine and let it sit overnight.  No problem so far.  However, when I try to restart the next morning it is difficult to get going.  When it does catch, a very rough idle persists for about 20-30 seconds. At no other time do I get the rough idle--only on the second cold start in a row, without a proper warm up between.  My service shop is stumped. Hope you can help.

Thanks,
Andy

Answer
Andy,
During a cold start the fuel mixture is richer (more fuel) so if you turn off the car cold it has not had the opportunity to burn all the fuel off. So on the second cold start the plugs are wet and a bit fouled until it warms. This will cause a rough idle for a short time.