I had almost the same thing happen & 105,000 miles. Rpm's went WAY up and had to stand on the brake approaching stop lights. No CEL though... It went away for about a week and was consistent high idle after that. Turns out the intake manifold gasket was badly cracked effecting all of the right bank cylinders! HUGE pain in the neck to replace but runs like a champ now 10,000 miles later! Since your CEL went on im assuming it may be some sensor, TPS maybe?
There is a service bulletin somewhere on a change in torque spec for the bolts on this gasket. Don't quote me but i think it changed from 16 ft/lbs to 13?