power problems?

It may be the o2 (or oxygen)sensor going bad located on the exhaust manifold, probably 2 of them. My 03 spectra did the same thing exactly, and it turned out to be the o2 sensor. If the check engine light is on, go to an auto parts and have them use a code reader to tell you what the cars computer says. Also the cars computer has 2 operating modes which are "open" and "closed" loop. In "open loop" it uses information from all the sensors to control the spark timing and fuel. (By unpluging the o2 sensor the computer will recognize their is no signal from the sensor and will run in "closed loop", which is a preset spark timing and fuel ratio from the factory normally used when the car is first started until it warms up good) Therefore, you could try unpluging the o2 sensor and if the car runs fine with it unpluged, then it is a sensor( most likely the o2 sensor) that is bad and causing your car to act up. Hope this helps, if not it could be a spark coil or spark plug wires going bad or fuel pump going out.