F150 service engine light

my service engine light(little illumination of a motor on dash board) is on. 2004 f150 5.4 litre. Book says it could be the fuel. I have run it low on fuel(never ran out). 54000 miles, Thanks Ron

It could be any of thousands of things. Get the OBDII codes scanned somewhere (some auto stores will do it for free), and report the codes back here. We can’t help otherwise.