'85 idle at start

[tgeej]

My 1985 spent 5 years going through a slow process of professional re-paint, and reconstruction. The engine was run occasionally at best. Now, at start-up the engine will usually start quickly, but idle rpms are low and usually barely continues to run. I can accelerate the rpms, but it will die if I do not gingerly slow the rpms. Any throttle reduction must be steady and slow. After several minutes of warmup, all is fine, and remains so even after sitting for an hour or so (still warm, of course).
Thanks for any advice, before I start swapping sensors and parts.

[zuch]

First place to look would be a vacuum leak. Check all of your hoses and make sure they are connected and not cracked. Check for loose intake manifold bolts. You can use a spray of carb cleaner around likely culprits and listen for a change in rpm which would then point you to your leak.