Hi folks- I have a 2007 Mazda 3, 2.3L (no turbo), 5 speed manual, 95K miles, second owner (bought it in July with 91K).  

Occasionally on cold start, the engine will stall.  This occurs maybe 50 percent of cold starts, and when it happens, the engine won't idle up and will sputter out after about 10 seconds.  Restarting the engine after stalling is never a problem.  I sometimes prevent this cold-start stalling by ever-so-gently revving the engine, and it will idle up.  Engine also sometimes idles a bit rough/shakes the steering wheel slightly now.  Rough idle started recently as the weather got cold, but this could just be a coincidence?

I'm thinking of cleaning the MAF sensor, throttle plate, and putting in new spark plugs.  From the service records I have from the previous owner, I think they are the original plugs.   Any thoughts??? Thanks in advance!