k well i have the 94 prelude (4th gen).....and anytime its idling....it bounces from 1000 to 2000.....i scanned it and it said either map sensor or idle air control valve (IACV)......which do you think it is?....cuz i dont wanna spend 200 on a map sensor and that not be the real problem.....cuz to me if it was the map sensor then the check engine light would be on but its NOT

 

you say you scanned it and got either map sensor or idle air control valve. that makes no sense. if you have a cel it sends back a code and you go from there. but then you go on to say theres no cel. you need to search it because whatever it is it has been covered. mgaga7 did a good write up. SEARCH IT