Check engine light came on. Is not flashing, but on initial start-up car will stall and will continue to stall when idle is low until car warms up. If I keep gas up so idle is up I can drive it until its warm. I had a tune-up (plugs, etc.) Done about a year and a half ago. Had oxygen sensor changed as well. Anything in particular come to mind, or are there many things that could be wrong?