(Tom Young- Computer problem? and Alex Sanchez- overheating)
 
With my lack of expertise, I'd normally keep my mouth shut,
but these two are talking replacing engine three times
(Young) and replacing the computer (Alex), really big
expenses, so any help might help.
 
Overheating: My van overheated some on our trip. I watched
that temperature gauge very closely. If it went more than
half way, I let up on the accelerator until it went back
down. To tell the truth, I actually put the heater on in 105
F weather to cool it down. I think BAD things happen if the
engine overheats. (The heater in 105 F isn't really that
bad, the windows open at 65 mph just blows it out and you
really don't feel it.)   
 
Alex: Do something to stop the overheating. Turn on the
heater even. Definitely turn off the ac and open the
windows. Don't let it overheat. I'll confess I have two fog
lights just a little obstructing the front lower air grill
work. Check for bugs, dirt or something obstructing your ac
condenser (the evaporator is inside, I think).
 
Tom:  Did you try turning the slotted screw, well not
actually a screw, it is just a about 1/2 inch round, with a
slot, to adjust, on the intake, where you'd expect to
twiddle and adjust. At various times, I twiddle this
adjustment (I just looked it up, it is called the idle
adjustment, it is on the main spring/turning point where the
throttle cable attaches. Don't turn the little screw, just
the big (1/2 ") slot.)  What I'm trying to say is, if my van
idles too high when warm, I adust this screw. It seems to do
nothing until you turn it a bunch and there is a proper way
to adjust it, measuring CO, disconnecting the O2 sensor and
idle stabilizer control valve connector. But just twiddle
it, I mean turn it 180 degrees one way, see what happens
when you drive it about 20 min, 360 degrees back the other
way, etc., maybe 90 and 180 degrees.
Russ