Hey guys thanks for your replies.

It's making me mad. Now I've tried it again and it started as I turned the ignition. I left it to warm up. Switched off and tried again... started no problems. Left it to cool... started without any problems. I repeated these tests several times and it has always started.

That's bad cause I still don't know what the problem is. And I don't want to make any funny shows in the middle of the road!

The fuel pump has been working fine for 3 years. I tested the pressure and it was perfect. Should I give a try changing the starter motor?