1987 legend with an intermittant idling problem.This legend may run and idle problem free for a month at a time. Then suddenly start to st~~~ at stops,unable to idle.Strangely enough turning on the A/C will sometimes counter the fading revs and enable the engine to continue running at stops, albeit with reduced revs.I have changed the fuel filter , plugs and added injector cleaner on a regular basis. Still a no go. problem persists on a intermittant basis lingering for a week or two at a time before returning to normal running/idiling.Any IDEAS ?