Sounds like a fuel delivery problem. Start off with the cheap and easy and go from there.
Replace the fuel filter. A new one costs less than $20 and should be replaced every 20,000 miles or so. Not hard to do and no special tools necessary.
If that doesn't solve anything, check the fuel pressure at the fuel rail. Not sure of the exact pressures, but should be around 40psi engine running, IIRC. If it is low, check the function of the Fuel Pressure Regulator by removing the vacuum line from it. Fuel line pressure should increase. If not, it is faulty. If it is still reading low pressure and FRP is functioning, your fuel pump may need replacement.