Weird problem with idling (help!)

[Davidaus]

I'm having a really unusual problem with my 15 year old forester. It drives fine on the highway, but then if I get into stop and go traffic the engine starts choking and then stalls out, very much as if it just ran out of gas. Then the cure is to let it cool off for 20 minutes. Then you can start it again and everything is fine. Also, if I just turn it on in the morning and idle it, it's fine. But then if I then drive around for a while and THEN idle, it sputters and stalls again. So, this is only when it's hot and when, first, I go fast and then idle. Something inside can't adjust down to an idle correctly. I've gone through several mechanics who can't figure it out. I'd be much obliged if anyone could explain it to me.

 

[Even]

i had a similar thing happen to my 2009 forester it got fixed by following this video:

another couple things it could be...
1: spark plugs (maybe cables too)
2: throttle position sensor messing up (you can have a mechanic check this with a OBD2 reader reading the live data from the computer) - ive seen this happen with damaged cables or a bad throttle position sensor. but try the video i posted first

 

[Deezbs]

Something very similar happened to me. I finally just happened to notice a spark come from the alternator. The bolt that connects the battery power cable to the alternator was loose. It was making contact only intermittently. Also, to me anyways, it sounds it may be fuel related.