I have a 04 ex civic coupe manuel tran.It has 101,989 miles.....today as I was driving on the freeway I noticed it started to sputter....and as I started to go up hill..it got worse...and seemed like it wanted to stall...and the ecl was flashing...well I got off the freeway and turnd off the car and...everything is fine now...could it be the fuel filter?

 

welcome to the forum. Yes possible, also possible condensation/water in the fuel tank.