Hi I got a 97 sentra, when in first or second gear there is no power from the car. If you put 1/4 gas or press full gas the same power is seen. The acceleration in these gears is horrible too. Also it struggles extra on inclines.
In 3rd gear the car starts to act more normal. also it seems when the ac is on it runs a little better.

Does anyone know what the problem could be? Also if more info is needed.

maybe bad gears, cant really explain it but how long has it been since your last tranny flush

sounds like maybe when your car is working 'hard' its normal....that doesn't sound right. check your fluids(oils, coolants, transmission). also do a check on your ignition system(wires, spark plugs, distributor cap)... it might be in those, check and if necessary change those fluids(ignition) items.

Does it vibrate at all? If so, it sounds like a misfire. Like a sparkplug or injector. If there's no vibration, I'd say the tranny's shot and is slipping.

Sorry, not tranny. I meant CLUTCH.

fugiot is probably correct. The clutch sounds like it is slipping. Start the car, put it in 3rd gear, rev the engine and pop the clutch. If the RPMs stay high and car barely moves, your clutch is bad. If the car lurches forward and the RPMs drop down until the car dies, your clutch is good and you have another problem.