just a question for what people might think this is.
Whenever I've been driving hard on the highway, after a while, the car idles twice as quick as it does normally. It idles fast for about 15 to 30 seconds & then cuts back to normal idle.
Air-conditioning & CD player are off.
the water flow through the idle control unit is not blocked at all, though perhaps the unit itself is faulty??
Though if I drive sedately around town, this doesn't occur.