Well you don't say what year it is but mine is a 92. It would run OK
around town, but to come home I start climbing a steep hill which lasts
for about 7 miles until I exit I-70 to go home. It would cut out and I
quickly found turning the key off and on again would reset it.

I guess it really was going into limp-home mode, but you have to let off
the gas and get back on it again to get into limp home (so the manual
says).

There is a solenoid valve on the firewall which connects a hose from the
traction control throttle thing to the valve cover through a check
valve. I replaced the hose from the throttle and that fixed it.

Could also have been check valve or solenoid valve.

Previous two owners had replaced everything, they said, but with used
parts.

You can find the failure codes using the blinking check engine light and
also reset it. See

http://townsendimports.com/Web/engine_folder/engine_systems_docs.htm

Good luck!

Charles