Quoted From dreamer2355:
Does the vehicle run fine once started? Usually, if you have an issue with a plugged fuel filter, it would hesitate under WOT.
You may also have an issue with the FPR and im under the assumption you have a return-less fuel system, hence the FPR is apart of the fuel pump assembly.
You should see a drop in fuel pressure if you hook up a fuel pressure regulator if that check valve was bad.
You don’t always get a hesitation with a plugged fuel filter. I have seen them hide pretty darn good but cause and extended crank or multi prime.