Hey do I've got a 2006 ZX4 S with a 5 speed and over last winter, I replaced the alternator. Come to this summer, and I've noticed an odd problem. Whenever it is quite warm/hot outside (20+ celsius) and if I get stuck in stop and go traffic, the battery light comes on and the idle drops for an instant to around 250 rpm, as if there is an excess load on the engine. I've measured running voltage (@1500rpm) and its around 13.7-14.1, which is fairly healthy so I don't believe it to be an issue with the alternator. The battery is around 3 years old but gets exposed to -40 temperatures nearly every winter. Also, the idle problem is not constant so I have no reason to suspect a vacuum leak. The car hasn't died yet, so I'm not too worried, especially since this problem hasn't happened when it's cold outside and its about to be winter here, but I really don't wanna be left stranded. Anyone have any ideas?