Backfires, won't idle

[jon]

'76 2002.  Backfire started a week ago. After a 20 mile high speed drive, the engine won't idle, kills unless revs above 2000 rpms.  Points gapped and plugs new.  What could be causes? 

[flagoworld]

Do you have an idle cutoff solenoid on the main idle jet?

 

[Stevenola]

Vacuum leak?

[jon]

carburetor is a 32/36.  The side you point to has a white plastic choke.  Will check to see if there is an idle cutoff solenoid.

 

The only vacuum line I am aware of to the intake manifold is OK.  There is another port that is plugged.

[71bmr02]

Sounds a lot like condenser.  Also, any time points are changed/gapped you should check timing to make sure it's still on spec.

[flagoworld]

If you do have an idle cutoff solenoid then that could be broken or disconnected and causing fuel cut at idle. But since it's also backfiring and what not I'm guessing this isn't your issue.

 

Distributor spin a little maybe? Make sure it's tight.

[conkitchen]

Is it back firing through the exhaust or up through the carb? 

 

I'm going in the direction of maybe a vacuum leak and timing 

[Simeon]

My guess? Blockage in the idle jet.

 

Have a look where that arrow on the picture above is pointed and you will find either a idle solenoid (as discussed above) or a idle jet carrier. If it’s a carrier, unscrew and clean out the jet in the end. 

[Hans]

I like the condensor idea.