after the car has been sitting('04 g sports coupe) for a while(4-overnight hours) and i turn on the AC i get a pretty bad mildewy(is this a word?) smell. wondering if anyone has had this happened(13,500 miles).

 

do you use the recirulate or fresh air function? you should use the fresh air. what happens with the ac in rec-mode is that all the moisture builds up and that what causes the mildew/mold to grow.

 

the A/C builds moisture no matter what, running the A/C will normally get rid of it.
You likely want to change the in cabin micro filter also

 

I have always used the fresh-air.

 

I ran her hard, and can't simulate what you smell, sorry! Id say its a problem!

 

After running the AC, humidity forms on the coils. Combined with in-coming air that contains mold/mildew spores, etc., they tend to grow in the moist conditions. It's best to shut off the AC for a few minutes prior to shutting off the car and just run fresh air to dry the coils off. This will prevent the funky smell next time you run the AC.

When you replace your In-Cabin filter, spray some AC deodorant or Lysol into the system and run it for a few minutes to kill the existing spores. That way, the new filter will keep things fresher for longer. Also, consider that the OEM filter is not really well built, and rather leaky around the edges. It's designed to filter mostly the larger particulate matter only and may not filter spores, etc. very well, so you may want to look around for a more efficient filter design.

 

since Gord is apparently far too modest to suggest it... I willl

Gord not only makes the very best Grounding wire set/system (Which I very highly recommend)
He also makes in cabin filters for our ride which are far better than stock, offer better fit, higher surface area and pleat count, and ativated charcoal !!!!

Don't waste time, send a private message to Gord, and get one/some.. I strongly recoomend them !!!!