Occasional slight judder when cold? 525i engine.
 

When I bought the car I found it hard to find any sort of major common faults for the petrol engine so didn't know what to check for? In fact it doesn't always do it.

Occasionally, the car starts up absolutely fine and judders a little until the accelerator is pressed. Almost like a pulse.

It only seems to do it if it's not been driven for around 2 days. It did it yesterday evening before I went to the cinema but when I returned it was fine. Not sure if it's lunpy enough to be a miss fire and goes almost straight away,

I'm probably worrying about anything but I haven't had the car very long yet. Any suggestions?

With as many miles(km?) as your car has I would say that some occasional shudders is not anything to worry about. With that being said, a basic tune up would hurt. The coils are usually an "all or nothing" part, so unless there is a misfire, I wouldn't worry about them. Spark plugs, air filter, or fuel additive might solve the problem. Also, I have a 96' Honda Civic that shudders on starts after a couple days too, but seems to smooth out once the motor is at operating temperature.

The car has quite a few miles on. 145,000 miles. Generally it's a very smooth motor. Miles don't normally worry me as I buy on condition more than anything. It's had a few items replaced recently but I'll get it into the garage at some point.