1991 Honda Accord EX: Revs up and down when in park or neutral. Pulsates when in drive, but only at a stop- unless I press the gas pedal to about 1600 rpm> Took off and cleaned Fast Idle Thermo valve (FITV), Took off and cleaned Idle Air Control Valve (IACV), unplugged Throttle Position Sensor(TPS)- no change, New fuel pump and filter... any suggestions?

 

Check for a vacuum leak. Check for cracked or loose vacuum hoses, worn or cracked intake and throttle body gaskets, injector o-rings.