engine idle

Hi all,I just bought a 1997 accord exr,the motor went on the previous owner,he didn't change the timing belt,expensive lesson,anyway he put in a h22 japanese motor,now i'm the new owner,and am having a problem with the idle,on start up it revs up to 2000rpm or so, but when I kick it down it goes low enough to allmost stall,it's very annoying at stop lights,everyone thinks I wanna race,I'm close to 50yrs old it's quite funny kinda,no one knows whats under the hood,has anyone got an idea of what may be wrong with this motor?,would it be the TPS sensor? just guessing,thanks for any input,and yes imports are quit impressive,200hp from a 2ltr engine,not too many north american vehicles can boast that.Cheers. Brad