96 Olds low power at times

[wwepatriot]

Got a 96 Oldsmobile Cutlass Ciera 4 Cylinder engine, and the last 2-3 months have been experiencing low power more so at lower speeds under 40-45 usually. It take so much strain on the engine and power on the gas pedal to pick up speed it got pretty ridiculous, at the same time the car would heat up on the temperature gauge (quarter mark) after a few minutes of it doing this, the car would also vibrate.

So I ended up changing Spark Plugs, Wires, O2 Sensor, cut off the catalytic converter and piped it in, got rid of the 2nd O2 sensor after the Catalytic Converter, changed air filter and intake.

Still has not fixed the problem, it improved some what, but still cannot pinpoint the problem. At times I have to turn off the AC to GAIN power.

Like to note it does not do this all the time.

any suggestions?

[13Legion]

How many miles? Could be low compression. Overheating could be do to clogged radiator or head gaskets.