Engine sputters once after starting, then runs normally

127000 miles spark plugs are Ngk Laser Dbl Plat/Spark Plug 6 months old problem has been happening for at least a year, so that's not it.

EVEN though that's not your problem...Have you done a visual inspection of the plugs and cylinders? If you know what to look for (beyond the obvious) then it might tell you a little more about what's happening in those first few moments the car is running...sometimes more useful info than a scanner . T-belt's been changed of coarse? New tensioner too? fuel pressure after shut-down has been checked(for internal leak-down)?

I looked at the plugs when I took them out, but they seemed normal. Haven't done any of the other things.

EGR? EVAP purge soleniod ,(Brief light clicking)?