Hello;  Recently my 87 GL has taken on another character trait.  after
running enough to get the temperature up, the idle stays at 2000 rpm.
Sometimes (about 1 in 10) it will drop back to 1000. Another (possibly
related) symptom is when de-cellerating the van will hiccup, similar to
running out of gas sensation.  I checked the engine compartment for obvious
problems, nothing, everything is tight with nothing dis-connected.  Oh, I
recently had the engine compartment pressure washed, and these symptoms
started after that.  What is the problem?  Where should I start?
TIA  Larry Carter