I found the vacuum line hiding behind the engine which goes to the back of the carb, and discovered it goes to a T for the dist. advance and a thermal switch. Looks like the advance was inoperable and the timing was way high to compensate... at least that's why I have to assume it was set so high. I reset the timing closer to specs.

The EGR valve is being ordered, as is the EGR thermal switch. Neither are going to work if the port on the carb wont unplug. I'm betting it's full of gelled up vacuum line. I replaced some of the lines, but need more.

The carburetor choke is worn out too. It will either close all the way when cold, or open all the way when hot, depending on it's set position, but it wont do both (BTW it's s'posed to do both).

i still think there's a problem with the A.I.R. pump (emissions equipment) but the stupid Haynes/Chilton's wont give me proper testing procedures, so I cant prove it yet. "This system is very comlicated and is best left to professionals" Baloney! It's a fairly simplistic system.. plus I am a proffessional, nyahhh.
But... I won't guess on how to properly test the system's diverter valves. It's not practical, and takes more brain power than i can muster on most days anymore. I'm fairly sure it is not supposed to continue to pump hot air into the exhaust during decell. Disconnecting it from the exhaust has no effect on the decell backfire though, at least not yet.
It's also not practical for me to buy a factory service manual for every vehicle out there. I have access to most info in the inexpensive Chilton's/Haynes manuals for many models, but they just dont always cut mustard.
mmmmmm..... mustard ;)

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scotty