The rpm going up down - 1997 Honda Prelude

probably in limp mode
have the fault codes read to determine the fault

This sounds normal to me. Why do you think there is a problem? If the RPM's are going up and down during acceleration, then I would say there is some sort of slippage. Have the transmission looked at for signs of trouble. Also, check the transmission fluid level for the correct amount. If it is low, find out why it is leaking. Gasket leak?

Clean throttle body,change air filter,then could be IAC sensor next TPS sensor(RPM).

rpm going up and down my 2005 tahoe

No,only on carburated engines it,idles down to the set point,on yours,it's fuel injected,pushing gas pedal won't kick idle down,should go down after a certain amount of time,does it automatically,If you start and drive a 5 mile ride and stop at a stop sign,it should idle at it's set point if there's no engine problems,which may be.5 to .7 on your tac.When you normally first start,it will idle between 1000 to 1200 rpm's,don't push on gas,let idle say 15 seconds,put in drive and go.

I don't really know where they should be in idle on your car, but if you don't apply your gas pedal, the RPM's should be low. My 18 wheelers RPM's are down to 500 in idle position and go up to 2300 when I step on my "diesel" pedal. If in neutral or park and you step on the gas...do your RPM's go up? If yes, all should be okay.

try to reset the computer if that doesnt work reset the idle speed it may have picked up bad codes

sounds like a fuel filter

hello it sounds like your throttle position sensor (tps) is out of range this controls your idle threw the computer what you have explained is a pattern to bad tps goodluck

It means your transmission is slipping, that happens in a lot of mercury mystiques.