I have a 2.3 16V that has an intermittent high idle problem. Every once in a while, the car would idle at 2800-3000rpms. Unplugging and plugging in the ecu will temporarily fix the problem. I've tested the idle valve, air flow sensor, eha, all sensors, micro switches, and components and did not find any problems. When idle is high, voltage from the ecu to the idle valve is at battery voltage. Also, not sure if it's related, but the lambda control will show to be inoperative when the problem is occurring. I've changed the ecu with an rebuilt unit, but it still has the same problem. Any ideas what i should check next? I'm still thinking we received a bad rebuilt ecu, but would like everyones input before i put in another ecu. Thanks for all your help. Thanks

Simon