You can test the egr by applying vacuum to the port and see if the engine stalls while holding the rpms up enough to keep from stalling now. If it makes it worse, then the egr vavle is probably ok. Maybe test for vac. leaks by spraying starting fluid around the vac lines and carb, if the idle goes up, you have a leak in that area.
You are referring to the 84, right?
Jeff

It's all good!
83 Shortbed stepside lots of mods
82 Shortbed fully restored
85 Shortbed daily driver
88 4-runner-Wife's daily driver