SC warm up issues
 

Start the car up she idles fine,[900] drive along shes fine for about 1/2 hr then idle goes down to 600 she stumbles and pops out the exhaust mainly on decel but loss of power. anyone?

I would say WUR: warm up regulator. It looks like once the car is warmed up, the mixture becomes too lean. It should be rich at startup, then normal. In your case, it leans up too much.
Just my .02 cents.

Since the car appears to run well for a while then loses power, it could be fuel starvation from clogged fuel filter, clogged screen in tank, or dying fuel pump that shows up with increased demand for fuel. How old is the filter and pump? There was a recent thread where someone had similar problems and found that the pump was drawing too many amps--replaced the pump and all was good.

If you have a fuel gauge set, you can test the system pressure which could point to the pump but an amperage test, especially when the symptoms occur, could be more indicative.

Another possibility could be a failing coil or some sensor that SC's have that I'm unfamiliar with but others may comment on.

Do a bit of checking of the above suspects and report any results.