Sometimes my car hesitates to start and runs rough

Do you have a CEL? If so, read it. Most common CELs for stumbling are misfires from wet or very old ignition cables that short to ground either at the coilpack or along their too- close draping near exposed metal. Codes would be PO30x, where X=1-4 to indicate which cylinder is affected. If no code you might have a dirty throttle body. Remove intake plenum and spray-clean thoroughly with carb cleaner solvent all around, inc while holding the throttle butterfly sprung horizontally to get a wet toothbrush in there. All this assumes you have nice clean plugs. If one is VERY oil-soaked clean it and chase leaky seal with oil stop-leak product for awhile before you pay to replace valve cover spark plug seals. Also check for something obvious like a detached air hose from the heads to the intake plenum, as these can pop off, thoroughly ruining idle and acceleration smoothness. Good luck. TheSubaruGuru/Boston

Hello: it sounds like you have Fuel System Malfunctions. Check: Fuel Pump, Fuel Pump fuse and relay (they) may be defective, Fuel System Operating pressure, defective fuel pressure regulator. thanks!