So I've been driving our recently purchased 98 V70 GLT for about a month now. Everything seems fine with it, with one what seems to be minor exception.

Every now and then, when at a traffic light after the car is warmed up, the idle drops down ever so slightly for a second or two. The best way I can explain it is that it seems like the AC compressor is kicking on or something is putting a load on the engine, but the AC is turned off (as is the defroster - I haven't noticed if this car turns on the AC whenever the defroster is on, but I know my honda does). Any ideas?