Is the check engine light on if so what codes are in memory. And by choking out is it flat out stalling at this RPM or is it surging at this RPM level. Will it dead rev in nuetral above this RPM and by that dont blow it up finding out but will it free spin over this point easily or is it just like without load.
Your description in not complete enough for me to help. Non Normal would be a plugged cat or low fuel pressure. But both fit the complaint.
Problems I see in this model similar to your issue are carbon on valve stems high RPM or loads cause missfires bad enough to even stall the engine. But it will have missfire codes and some other issues.
Plugs wires and coil issues generallly will reduce power at High RPMs but will gernerally not keep one from reving into the red. They are often the main cause of high RPM loaded missfires.
From time to time I see failed Mass Air sensors which could cause a full out hesitation or flat spot a a given ROM but I see more hesitations off idle on these than any other complaint.
I would do a couple of simple things first I would make sure its got proper fuel pressure should be 35 ish normal driving and up to 42 ish at Wide open throttle under load. If you dont have a fuel gauge get it tested. Fuel pumps arent that common a failure on your model but I do see one from time to time.
Next step would be to find a known good mass air sensor lives in the air intake tube right behind the air filter. Rebuilt are junk new are about $400 so find a known good one its a ten minute swap including the road test so maybe you can borrow one froma buddy.
Coolant temp sensor fail on these a lot if they are out say 25 to 40 degrees it wont set a check engine light but will cause some screwy performance issues scan tool is the simplest way to test it. I figure 5% of actual engine temp at the head is max it can be off you need an infrared temp gun to compare along witha scan tool. but you could ask a shop to make sure they perform that and fuel pressure. Just make sure its acting up when its tested.