I did IACV and the throttle body clean. The mild idle shake is still there. The van driving was smoth when speed was below 60 miles/h, but seems to be kind of up and dwon when speed was above 65 miles/h. One of mechanic said is a sign of distributor issue, and the fuel injector is ofen issue on Nissan V6 engine. I would like to hear from you. thank!