1996 Dodge Avenger fuel issues

I bought a very used 96 dodge avenger with a 2.5ltr. The vechicle sat in a garage for 4 years.The previous owner stated the car has a hesitation on acceleration.I bought the car drained the fuel from the tank,changed the fuel pump,the fuel filter.The vechicle gets proper fuel psi.When the vechicle is running if you feather the accelerator pedal there is a stumble.When its running at idle it misfires or puts.If the vechicle sits over night it will crank but not start.If i spray a touch of starting fluid in the throttle body it will start up.I was curious if there was an issue with the fuel psi regulator?The shut off valve?Something possibly along those lines.There is no misfire codes or any hints that possibly the injecters would be clogged.Im really lost any help would be appreciated.thank you very much.