my car was doing that too... cept if i pressed the gas a certain way... the rpms would adjust automatically somehow, and sometimes it would idle at 1500.
i later found out that hickups and stutters are mostly caused by your spark plugs. if you rev high all the time, your sparks will burn out, thus giving you a lower "energy" level.
cmon, tell me, do you rev a lot?
i redline all the time, and I have to replace the sparks every 3K miles. Its real cool, since I dont care if my car blows up. When it does, ill just get a CRX.