2002 Toyota sienna 100000 miles

What is your question?

Driving on HWY around 60 miles per hour and engine hot, engine starts to run erratic and after a while check engine light will come on. After engine has cooled and now driving at lower speeds engine runs normal and engine light will go out. New Spark Plugs did not change anything.

How long has your 2002 Toyota Sienna had this problem?

A few weeks