the plug should be located by the ecu. Not sure what to make of that site you posted though. Alot of times, in the h, you can fix your fluxing idle by screwing down the fast idle valve.

 

there are a cuple of things tha causes this in a honda, a vacum leak, the idle screw, and this bitch sensor under the distributor that tells the computer that the engine is warm, at the trotle body there is a plate towards the fire wall and a valve its in there called fitv, with time this valve becomes loose, make sure its tight abd back it up just a litle. also check the ecu codes to narow it down. these are all the ones that i have run into, good luck