I was also getting a blippy idle once the car had warmed up which eventually went away, I presume through heat soak into the valve. There are two idle control valves on the engine, one is controlled by the ECU and another works like a wax thermostat which closes off an extra idle air path when warm. What was happening was the extra idle air flow path was staying open due to no warm water flow and the ECU didn't have proper control of idle speed which resulted in the blipping, I also noticed that the small bore water pipe of the bypass circuit wasn't getting very warm. The bypass circuit warms up the intake manifold, throttle body and some other parts so this must have affected warm up too. When I took this valve off to clean it I needed a drill to get through all the corrosion!
I sorted all this out ages ago now, just thought it was worth pointing out to others as it took me ages to work out and I have seen the same problem on 3 engines now...
|