Hesitation, stalling and weird idle

So before I throw more parts at this thing I would like some kind of opinion on this. I've changed the spark plug, wires, fuel filter, air filter, cap, rotor, ignition coil, fuel pump relay and fuel pump itself. And my car still hesitates when I press the gas, it stalls if you don't let it warm up and when you first start it in the morning the RPMs go up and down for 15 seconds before acting normal. Anything I am doing wrong besides throwing parts at it? I've done a lot of Googling and can pinpoint my problem. No check engine lights either.