2001 WS6 idling issue
2001 WS6, 6 speed, 104k miles.
Mods = headers, 3.73 gears, y pipe, cutouts, MAF.
I bought this car used with about 102K miles. In the 2 years I've owned it, I've had 3 instances where the car has started idling really low when at a stop, and eventually has died. It starts right back up. This has only happened in hot, humid weather. 99% of the time, it runs great.
What could this be? Should I take it to the shop where the previous owner had it tuned?
Thanks in advance.

