possibly ecu problem? Need help
 

I just did a swap of 2001 gsr into 2000 civic LX. Because of the immoblizer in the 2001 gsr ecu, I have been using 2000 si ecu. The car runs wells and ocassionally has misfired. But when I put the 2001 gsr ecu in (after it got programmed by the dealer), I get misfiring all the time. Also the idle speed move up and down. It stay up at 1500 rpm for about 5 sec after I release the gas paddle, then fall back down to around 900 rpm. The car is jerky and I can feel the engine vibrate. Someone told me that it is the fuel pressure problem or I need a new fuel pump from the acura, and not the civic. Someone told me that it is the ecu? I need some serious help. Thanks