How can I fix high idle?
In theory once the desired idle speed is programmed into the management system, in the absence of such faults as air leaks, sticking idle air control valve and suchlike it should be impossible for the idle speed to be much different from the programmed value because the ECU should continue closing down the amount of air bypassing the throttle butterfly until the idle is around the correct value.
I think you need to go back to basics and double-check the work to ensure everything is as it should be. In the absence of mechanical faults and ignoring the possibility of electronic problems a high idle must be caused by too much air entering the engine, either because the idle air control valve is not closing properly or because the throttle butterfly is not closing fully.
It is worth noting air can enter the intake through leaky diaphragms, split vacuum hoses or faulty pcv systems. It is also worth checking the egr valve if fitted.
Jan 24, 2016 |
2006 Chevrolet Cobalt SS