thanks, P!
Have you tried whacking the bid up? I once had a single keyword, for "brandbrand widget" I was at number 1 for 0.20 for "brand brand widget" I had to pay 6.00+ so it can happen that certain terms behave in an unexpected way.
my first gut feeling is, that ad groups with very tough keywords (like "car") are on hold until someone looked at it in person?
but if you say, it could be the case it probably is! so - conclusion - if you want to have a campaign running right away, use granular long tail keywords?