Okay, was driving my 04 Disco w/80K yesterday and after exiting the freeway and sitting at the light I hear the secondary air (loud whining sound) kick in for about five seconds then quit. Now, the wife usually drives the Disco but I don't remember the secondary air coming on before other than for a minute or so after a cold start in the morning. Could this be a symptom of something coming on? Perhaps my O2 sensors or cats are getting tired? I always run premium fuel and full service was done at 60k with plugswires etc.

 

I'll give you a bump and a I have no idea. Maybe somebody else will pipe in.

 

My truck has done the same thing a couple times. I have heard its got something to do with the mixture of gas etc. but I really dont know.

 

it really shouldnt ever engage your sai pump anytime after about 12 minutes of engine being on, however it is controlled by a relay, so you might want to check that that relay is not making accidental contact and that your fuse box is in good shape, if it just happened the once, dont stress it much, but keep an eye on it