I have an issue with a 66 FHC. The car had some missing and bucking during acceleration a couple of months ago, but it seemed better after clearing out some old fuel. Since that time, I have only had a chance to drive it a couple of times in town and was unable to duplicate the problem. Today it started all over again:

* It starts and idles beautifully.
* Theres a little hesitation before fully warm, but all my E-Types will do this to a certain extent.
* The situation continued to worsen as the drive progressed.
* I completely drained the tank, cleaned the pickup area and added new fuel (no change).
* Ignition wires, coil and plugs are all pretty new and look good.
* Carbs have been recently serviced and tuned.

Any ideas of where to look next?