I have a 1985 Nissan pickup that has a very intermittent problem.
It seems to be carb icing but none of the normal fixes help.
Just to describe a typical drive, yesterday morning I left home at about
9am, it was in the mid 30s. I drove about 20 miles, half of it on the interstate
crusing a 65mph with no probelm, after exiting the interstate and driving about 2 miles the motor
lost power and died. I sat about 1 minute and it started right up and ran fine
for another couple of miles and died again. This went on for the rest of the drive,
After setting for a couple of hours I drove it about 15 miles, made a 5 minute stop
when I started again it went about 1/2 mile and died. Started right up after about
1 minute and drove another 15 miles home with no trouble.

It was in the shop a couple of weeks ago for 5 days, they changed the fuel filter
and the distributor cap and rotor button.
The warm air pipe from the exhaust to the intake is in place and the damper
in the aircleaner snout is working.

It has never failed to restart.

Does anyone have any ideas for what I should do next, beside drive it to the junk yard???

If I take to a regular garage they'll drive it around to block with no problem and say
it runs fine...