Fuel filter? Ditto!!!!

I am sure that this is your culprit. Blockage just builds up over ride time and under system pressure.

Had the same thing in my 450 sEL. Started strong, then got weaker and ehsitated.

New filter will help much. Have it done right.

You may not notice difference immediately upon installation. Srive it gingerly for about 2-3 days, slowly increasing acceleration.

Let us know.