2002 Sentra bogs down in 3rd 4th and 5th

[NCYankee]

I test drove it today, 116K miles - pulls strongly to redline in 1st, also 2nd most of the time but I did notice some minor hesitation there toward the end of the test drive. The problem seems to get worse the higher the gear - it feels like its starving for either gas or air, it starts as low as ~3K RPM.

Nothing I or a mechanic I trust can explain why it would do this only in 3rd gear and higher - I mean the engine requires as much air and gas at 6k in 1st gear as in 3rd right? So I was hoping someone here could enlighten me as to what the problem might be.