I have a 1999 Honda Accord with about 120,000 miles on it. It runs great except after I have been driving at freeway speeds or after a smog check. When speed slows down after driving at 70 mph+, the car continually dies. The same thing happened after a smog check where they reb the engine. The ignition switch has been replaced and it has been in the dealership where they stated they couldn't find anything wrong. I am not afraid to take it on any trip that the freeway is involved. The spark plugs, the wire, air filter, most everything has been replaced. Any suggestions or help? Thank you!

 

Check the IAC is working correctly. Verify it is not blocked of coked up with carbon residue, same with the throttle body.