Pulling my hair out (if I had any)!, Surging idle that won't go away Options

[mpoffers]

I've had this 75 1.8L 914 for nearly two years and I have yet to get a decent idle. When I first start the car it revs up to about 1800 rpms. After 30 seconds or so it dies. If I set the idle adjustment high enough I can get it ot to keep running, but even then it ALMOST dies, then surges up to 1500 or so, then cycles back and forth. With the idle set high it is reluctant to rev back down when I let off the throttle.

Other that that, it runs pretty well. It pulls strong as expected at all revs. It's fun to drive, but blipping the throttle gets really tedious in any sor of traffic. It even passed Oregon DEQ. The idle problem isn't as bad when the engine is hot, but it is still there.

Per advice from you guys, I did a valve adjustment, set the dwell, checked the timing, replaced fuel hoses, and replaced all the vacuum hoses. I replaced the gaskets on the oil filler (flat and o-ring). I tried spraying suspect connections with WD-40, but no of them caused a surge.

What's left to try? Can I start disconnecting and plugging things that aren't needed at idle (decel valve or emissions stuff) to try to narrow down the problem? I suppose I could take to A&P in Portland, but I hate to admit defeat.