Can't rev engine above 2000rpm when in neutral

Don't roll in neutral, it's not safe

Sounds like an ignition misfire. Is the check engine light on ?

sounds like a transmission, try to shift it to neutral after you reach 2000 rpm + and see if the whining will stop

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is this gas or diesel,,, one of these is yours, and we cant guess it.
what country, this can change what EFI car uses. if any.

1.0 L D4D I4 (petrol)
1.1 L TU1JP I4 (petrol)
1.4 L TU3JP I4 (petrol)
1.4 L ET3J4 I4 (petrol)
1.4 L TU3JP I4 (petrol)
1.4 L TU3A I4 (petrol)
1.6 L TU5JP I4 (petrol)
1.6 L TU5JP4 I4 (petrol)
2.0 L EW10J4 I4 (petrol)
2.0 L EW10J4S I4 (petrol)
1.4 L DV4 HDi I4 I4 (diesel)
1.6 L DV6 HDi I4 (diesel)
1.9 L DW8 I4 (diesel)
2.0 L DW10 I4 (diesel)

to work on any car engine, whats under the hood(bonnet) counts.

If you have a hih miles truck,it is very possoble you have aclogged cat.Have a muffler shop test pressure in front and behind by drilling small holes,checkin w/gauge,then welding back.This should be free if you replace the cat.

different airflow meter calibrations,do you have the z32 airflow meter installed?

disconnect the battery for 1 minute and re-connect. start the vehicle and hold the revs at 1800-2000rpm for 10 seconds let the revs lower on their own then turn the a/c on and repeat. this will reset the base idle of the engine. remember all of these steps should be carried out in park or neutral, handbrake on.

Check for vacuum/intake leaks.

Do It Yourself Diagnosis and Repair

Have the alternator tested. You are providing a low charge to the battery when you jump it and when taking it above 2K RPM requires more amperage resulting in the engine dying and the rough idle

Check the oil level in engine.