Out for a little drive and everything fine for an hour or so. Then out of the blue the car starts idling at 3000 rpm.

The cable isn't snagged. The clutch has no impact. The cable at the linkage is normal; linkage has no tension.

These are dual 40idf webers.

Where do I look? Like the car is possessed.

Major vacuum leak somewhere.....or some grit somewhere in your linkage. Listen for the vacuum leak with a piece of hose to your ear or get the propane torch out and poke it around (don't light it of course!) and the idle speed will change when the propane gets to the leaking spot.

Advance mechanism in distributor could be stuck in the advance position.

Had this same thing recently. http://www.914world.com/bbs2/index.php?sho...=244094&hl=

A vacuum leak with carbs is not going to cause a high idle. You should break out your synchro tool and measure the flow on each throat. If they all read the same the problem is elsewhere.

I checked quick last night. There is no tension on the accelerator cable so it's not caught on anything. Linkage is at full rest.

I don;t know about a vacuum leak, I don't have any vacuum hoses on the engine.

This problem happened all of a sudden. The car idles perfect and smooth; just at 3000-3100 rpm.

I have the 009 distributor. If IT is stuck, would it really hike the idle up that far?

And the carb linkages are at the full stop position when at high idle?

Yes, acting like it has a choke.

Are the butterflies in the carb closing all the way? Maybe there's some dirt jamming it.

Listen to Kevin's advice. The snail gauge will give you a "go/no go" in terms of the synch. If there is an issue there, it'll point you immediately in that direction.

If no issue, I'd try actuating the throttle on each carb with car off - do you notice anything at all funny? Spend a couple minutes moving both through the full range. This is what Valy was getting at.

Of course, look for any missing bolts, nuts, etc all around the bases of the carbs and the intakes.

While the engine is cold and static, take a feeler gauge and check to see if the idle speed adjustment screws are off of the stops.