Hey guys i'm new here and lately my 93' honda prelude has been doing some weird idling things such as:

when i start my car it will be fine (idles around 1k)
then i'll drive it around town and it'll be ok it may dip down to 750 at stops but nothing crazy...
when i take it out on the highway after running about 55-75mph on the road for a minute or two, when i come to a stop it'll just idle down and stall. It's getting to where it stalls a lot now after it's been running on the highway. I had someone set the idle a little higher (around 1100) and it kinda helped but still once i take it on the highway and let it run fast for a minute it'll stall when i start to stop. any ideas? thanks in advance.
nate

 

bump

 

check your temp sensor