Check engine light on sometimes solid and sometimes flashing

Yesterday by 2012 ford taurus check engine light came on.
It was solid. I began to drive to work. Light started flashing.
I had run gas low day b4 and put gas in. I turned around
and went home. I put dry gas in .I unplugged battery to
reset light.  Light stayed off so drove bout 5 miles to work.
Started car up after work light back and flashing. Went out
2 times at red lights. Bout halfway home it stayed off. This
morning I started car light on and solid. Letting car run in
garage for awhile to warm up and see if it goes out. Any
ideas? Spark plugs were just changed bout 1 month ago.