I have also heard of the cylinder wall cracking if run too long w/o coolant.
After all, they are just thin sleeves. This causes pressurization of the
cooling system in the same manner as does the leaking head seal problem.

Now the question - my '88 fails smog check (CA)with too high HC at idle, but
does fine at 2500 RPM. But it also will rev up to 2000 RPM or higher on it's
own, usually when warm. Blipping the gas does not cure it. I believe the two
are related.

The accelerator cable is not sticking, the O2 sensor is fairly fresh, I
opened and looked into the airflow meter, and it looks ok, and measures
within specs, resistively speaking. I believe the temp sensor (left front of
engine) is ok. I've checked all the grounds and electrical connections I can
find, and am considering doing brain surgery to it next.

Ideas?

Thanks,

Ron Antaki