Idle seems to drop to around 250 and sometimes

it sounds like a idle control valve if you keep your foot on the gas alittle does it stay runningif so does it sound normal if so it probably your idle control valve and to should be on the back of your trottle body also try cleanind the inside of your trottle body with a lint free rag and some trottle body cleaner make sure you open the butterfly and get all that carben out of there sometimes the carben build up will also cause a big drop in rpm.