car cuts off when I stop after 11/2 hrs plus on hwy. After abt 10secs starts.

What is your question?

Car runs fine otherwise. However, check engine and airbag lights stay on constantly. Does not cut off driving locally. HAve new spark plugs/wires. And yes speedometer needle come on after abt 20 mins on highway. Sometimes, between 35-45mph after starting out there is a slight engine buck.

How long has your 1995 Lexus LS400 had this problem?

About 1 year.