i have a 99 integ gsr..id say on estimate every 1 out of 5 starts of my car..it would start with ease but when i start it..it would start and then i would notice the rpm hesitating at the lower rpms to try and have a normal idle..then it jumps to 1100..and a few seconds later go back to normal 750 and stay there..what could it be? spark plug change maybe?