3.0L starts ok but after warmed up and at a stop it starts to hesiate-when you hit the gas it is very sluggish - any ideas?

YOU MIGHT TRY LOOKING AT YOU FUEL FILTER.GOOD LUCK

fuel filter changed - still same problem

Before dig deeply into problem it is very desirable be sure that on the surface everything is OK. Just go ahead few next consecutive steps since fuel filter is already done.I'd check an air filter, positive crankcase ventilation /PCV/ filter, which is located inside of air filter housing, right below air filter itself,penetrability small piece of hose,connecting air filter housing with sleeve on the rear bank valve cover, and penetrability of this sleeve itself. Penetrability of small piece of hose, connecting positive crankcase ventilation valve /at intake manifold/ with sleeve on the front bank valve cover and penetrability of this sleeve itself. Workability of PCV valve itself, which in reality is one way valve /toward intake manifold-GO, from intake manifold-DOES NOT go. Integrality of all vacuum hoses and- absolutely important- suitability of fuel pressure regulator vacuum hose. Absence of a carbon dust and corrosion of metal inferences inside of the ignition distributor cap. Finally, I,d check injector fuel pressure. This check is highly recommended to perform in nearest trusty shop, on account of high fire risk. Also very desirable to add into fuel tank a fuel injector cleaner. Moreover, conducting fuel pressure test need to pay attention upon how steady is fuel pump noise /best way is to apply ear to the board of vehicle/, or/or both/- how much hesitate fuel pressure by observing how much fluctuate of a fuel pressure gauge needle. This is necessary to determine how fuel pump electric motor brushes are worn.