[Boxstard]

My air pump turns on at cold start-up then shuts off after 90 sec or so, just as normal. After a few miles of driving, idling at traffic stop, the pump often comes right back on for several seconds then shuts off again... What could cause this?

I thought the pump is triggered by engine temp/ cold start, so wodering if the temp sensor is gong out, or maybe any other component is suspect? My water temp is reading the way it is supposed to, on dash gauge and through 'hidden' climate control monitor.

I appreciate thoughts from those experienced.

PS. I'm planning t go through the secbdary air injection system to check vacuum leakage, etc.