85 Cabriolet problems in bumper to bumper...

Hi guys and gals,

I have a 1985 Cabriolet that will run all day long down the freeway,
but when I get into stop and go traffic, the engine will eventually
begin to cut out. Sometimes I can start it up and drive some more,
other times it won't stay running until it cools down and then
everything is fine. It's almost as if the engine gets flooded. Could
the cold start valve be coming on during the wrong time? I may be
imagining things ( as I was parked along side the freeway this
afternoon ), but I hear a noise under the hood that I don't normally
hear when the car does this.

The car idles fine when cold -- goes up to around 1300 and gradually
drops as the car warms up to 900 or so, occassionally drops below that
and then kicks up temporarily to 1000. ( idle stabilizer ).

I have not troubleshot fuel delivery issues in the past and that's the
one area I'm a bit leery of trying myself. Any ideas of things to
look at or things to try before I take it to the shop?