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I have a '66 coupe, 289 2bbl that I purchased a few months back. It's pretty much bone-stock original, the original owner took fairly good care of it. As I'm playing around with it before a restore this winter, I've been trying to get out and drive it around. I've replaced almost everything in the engine bay, short of touching the engine itself: cap, rotor, points/condensor, wires, oil filter, belts, spark plugs, rebuilt the carb, battery & cables, fuel pump, starter, solenoid etc. This is just to freshen everything up so its drivable in the meantime.

The problem is that at idle, it revs itself a bit every 10-25 seconds. Nothing horrible, just a medium rev. Additionally, when you're going 10-35 mph, it has a little bit of a pull on it. The best way I can describe is like when you're towing a trailer that's bouncing up and down behind you- each bounce causes a reaccurring light tug. Well, that's what this feels like, a slight surge every two seconds.

Thoughts?
 

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Sounds like it's coming from the carburetor. I'm guessing slight vacuum leak. Block off the airflow to the carb with your hand while it's running and see if it smooths out. You might also try adjusting the idle circuit set screws (if you are flowing too much fuel and it puddles in the intake, then dumps into the cylinders, it could cause symptoms like you describe). Other things to check are fuel filter and carb float. Others will chime in with suggestions, I'm sure. Good luck! ::
Daniel
 

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It's probably either a lean surge condition (vacuum leak?) or the points. Sometimes a worn breaker plate will cause erratic timing that will result in a surge.
 

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I have known of a floppy timing chain causing symptoms like the low speed surge every 2 seconds you describe. However, that's probably not your problem since you are experiencing the more infrequent surge at idle. That sounds more like a vacuum leak, or a possible carb problem as suggested by others. Be sure to give us a followup post on the cause, after you get it solved.
 

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I had/have this problem too. I was told it was the carb or a blown intake manifold gasket. Replaced carb and intake (and ofcourse the gasket) and the problem continued. I was then told it was the points. Adjusted the points and car worked wonderfully. My dizzy is all screwed up though, so the points sometimes close themselves. But, while they are at the appropriate place, the car runs like a dream.

I would check that first, seeing as how it's the easies thing to replace and/or adjust.

Good luck
 
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