my civic 95 sohc rpm fluctuate when i switch on the air-condition. the air -condition also blowing the plain air. the problem usually solved when i disconnect the MAP sensor and then hook it back again. but yesterday, i drove the car in a long journey and then this thing suddenly happened. this problem seems cannot be solved after i have done the seems method. i have no idea why it has something to do with air-conditioning system. i search through the forum and cannot find the exact answer. please help me. the weather here is too hot and i cannot drive without air-cond system. my sweat is dripping and it is very uncomfortable.

 

The A/C is a heavy load on the engine that effects Manifold pressure. If you are not having any other engine symptoms it may just be that the rubber O-ring of the MAP sensor may not be sealing anymore. Probably the original now 20 year old rubber O ring.

The O ring is part #16075-P07-000 about $3 or you can get a similar O ring at a hardware store.

Put some silicon grease on it just to help seal.

 

thank you for your info. i will find out the o ring at local store tomorrow. before i read your reply, i'm doing some cleaning work to the IAC . took out the IAC there are 2 hose connected to the valve. mine is look similar in this picture below. what I see there are water dripping when i loosen the clip. Is that hose for cooling liquid ?

 

yup it's coolant..

 

so the o ring for the MAP sensor locate inside the sensor and nothing to do with IAC valve? lets give it a try tomorrow as I still didn't sure what causing this and I will update it here. anyway thank you for the part #

 

i had replaced the o ring but it looks like the idle problem can't go away. even the o ring on the MAP sensor still look good.

 

UPDATE: Solved!!! actually the air-condition compressor belt already broken mid-driving and the leftover dropped somewhere on the road. sent to workshop for diagnosis, the mechanic told me the belt for compressor are missing. it's funny how i didn't notice that thing was already not there. i replaced all 3 belts, for alternator, compressor and power steering. now my rpm back to normal.