I have a 22re that has a random miss after the engine warms up I have added injector cleaner adjusted trmming change distributer cap fuel filter new runs fine don't really notice except idle or lower rpm runs smooth until it idles down and is warmed up anyone have similar issue and what you find out

 

Could be as simple as a "cat fire" (reaction of hydro carbons built up in the catalytic converter creating an upstream shock wave), or missing pulse to the ignition system from the distributor sensor (NE signal)..

A little burble here and there isn't something I would worry about.

 

Its probably a tune up or bad choice in spark plugs. If its the distributor which from old age is possible, get a Rich-Porter unit. More expensive but apparently they do extra testing to ensure it actually works before shipping out. Its also possible you camshaft is wiped, you have to see if the mountains are hills by now, I know that will do what you describe.

 

It might be the Throttle position sensor?

http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml