I am experiencing a peculiar intermittent problem with my idle on my 85
1.9L.  It starts fine and runs OK but the idle, even when fully warm, idles
at around 2000-2200 rpms.  When stopped at a long light, the rpm does return
to normal 800 rpm sometimes, sometimes not.  Any idea what causes this?  My
concern is that while it is not overly troublesome now, it could leave me
stranded somewhere.