a friend of mine has a dohc zc just like the one i have for sale anyways he calls me over for some help saying it doesnt idel right. i go over we start it up and everything is running fine than all of a sudden out of no where its atarts to pulsate from 1000-3000 rpm for ohhh about 30 sec than stops and back to normal. we take it for a spin and it would even do it while hes driving but if it happens while hes driving if he tries to give it gas it just boggs but about 20 - 40 sec later it will stop and everythings back to normal. some times it may even stay ideling at 3000 rpm and than 20 sec later drops back like normal. i checked for air in his coolant i checked his resivor and everythings fine , i changed his coolant temp sensor, changed his fast idel changed his tb and it still does tha same **** anyone have a idea ???