Runs rough then perfect

Change fuel filter

if still persisting after fuel filter change, then check sparkplug wires for arcing. replace bad wires.

Changed fuel pump, filter, idle control valve. This all started after replacing fan motor relays, coolant temp sensor and thermostat. Run fine for 15 minutes then acts like it is starved for fuel then runs fine again. Will air in system cause this?

Also had ignition control module checked. It was good

i'm also wondering if it is bad gas.. i had that symptom in a company van. switched gas stations and it ran better.