Cost inlet manifold

Well I have had the car only 2 weeks and the engine management light came on. Fault code said it was the inlet manifold. I hear this is a common problem with these engines. Now I do have some warranty from the dealer I bought it from, but you usually only get paid out when there is a complete failure. I took the car down my local garage, where the mechanic worked the inlet swirl valves with the lever on the side, just to free off possible sticking. He then reset the code. Driven about 20miles since and the engine light so far has stayed off. Just in case I have to fork out at some point on a new inlet manifold, I just wondered whether another owner on here has had the same problem and how much you paid for a new one. I really can't believe it, as my previous car a Mazda had the same problem a few months ago. That time I bought a second hand one which worked perfectly. Why second hand, a new Mazda one was about £700. Cars eh!!!