toyota4x4dmination

i have a 91 toyota 4 runner 3vze 4x4 sr5 automatic i purchaced it with 210xxx miles on the clock all orginal tranny engine ect it idled rough from the get go i replaced cap rotor wires( yes i put them on correctly) then i did the fuel filther and the spark plugs are the bosch best ones they offer witch were clean i checked the timing (properly) its good i have spark to all cylinders so then after all that still no change vacum lines are all correct also so then i ran a bottle of sea foam through the gas tank it actually helped to improve the rough idle but its just not right still i was wondering what else to check before i take it in to a mechanic and let them mess with it. whats the best octane to run at 6000 ft? would being at 6000ft altitude affect it? also how do i check that the egr sys is operating correctly? (o2 sencor also replaced) This seems to be a well known issue rough idle any help much appreciated

drmix

What does it idle at? Does it surge or stay steady?