Nobody can figure this out, it’s been happening for 10+ years.

It occurs at low speeds like city driving. Hasn’t been an issue for freeway driving.

Seems to happen more often when car is cold although it happens in warm weather too.

Happens mostly with heat, defrost or AC on.

I’ll be driving along and it starts making a fog horn sound in front end area for a few seconds and fades away, sometimes resulting in engine dying. Starts right back up.

Only thing I’ve heard over the years is...

2001 GT loud “fog horn” noise in front