[V8] ISV

[bw at UDel.Edu]

I have a similar problem with my "92.  The idle will not hold and begins to 
decline/hunt to 500rpm from 700+. This happens if I have down shifted (the auto) 
or accelerated (in S). I get a muffled backfire or a hesitation hiccup first. 
It is like "vapor lock", because it is always a hot engine on a hot day. It has 
symptoms of rich running, smell of gasoline when machine is at idle and uneven 
running (will often slow from regular idle rpm's and stop).
A new hall sensor and TPS helped, but something else??? Where is the idle switch 
and idle stability valve? I am sure this is a common problem. Thanks,  Bob