After my last long hwy trip out west, I returned home to discover an unusual noise under the hood. The noise appears to be a valve that is opening and closing once the car is shut off. It is not a clicking noise but rather something mechanical that is opening slowly and then closing slowly or visa versa. Also, I believe the noise is in the vacinity of the EGR and AACV. Would either of these valves make the kind of noise that I have described? If so, is it a problem? If not, what else could be the problem? Thanks for all the insight!!

 

^^^ This above is an old post. I 'm bumping it up to find out if anyone has found out what this noise is as I have noticed the exact same thing on my 95. It also looks to me like it's coming from the IACV area. I have also noticed the noise when I turn the screw to reset the ECU. Everything seems to be working properly; I am just curious to find out what the noise is.
Anyone have any ideas?