My Ur-Q usually starts pretty easily, and idles fine, but if I let it idle for any length of time to warm up it gets progressively rougher and finally cuts out after a couple of minutes (e.g. while I am scraping the ice off of the windshields). It will again start with relatively easily, but then seems to have great difficulty in transitioning from idle to the normal operating mode (excuse the non-technical terms), and stumbles, misses and backfires and threatens to die if any load is placed on it. This continues for some minutes, and I normally have to rev it almost to 3k once or twice (which I hate to do when its so cold) before it finally settles down.
This also happens if I catch it before it cuts out initially if I have let it idle for a while, whereas if I drive off immediately after starting it is much less prone to the pronlems with pickup from idle.
The only oddity that I am aware of is that the cover is missing from the idle and WOT switch. The car is new to me and I have been living in an hotel so I have not yet had the facilities available to get in and check all the vacuum hoses etc.