Yes, shifting the transmission at higher RPM's is like dumping the clutch. It will put the engine under a heavier load then from normal idle RPM's (700 or so).
I don't know about your high idle problem, could be any number of things. Here is the service manual in .PDF
http://tech.hybridgarage.com/tech/ma...e%20manual.pdf
Perhaps there is an idle adj. screw on the throttle body.