Low engine power

144,000 mi.
My car was running fine last week, I pulled to a stop to get some dinner, when I returned to the car and started it, it idled very roughly and seemed to have very little power. I have changed the coil pack, spark plugs and wires. It has a new O2 sensor, Idle Air Control valve, Air filter. The car currently is becoming harder and harder to start, it seems to require me giving it a lot of gas before starting and when it does start it idles out roughly still, but as soon as I put it into gear it dies. I have tried giving it gas as it was put into gear and it seems to lack significant power almost as if it has no lowend. I hope you can help