No, the intermittent 900-1000 RPM idle is a well documented issue with the 86/87 cars. The cause is not clear, but it's definitely electronic. Even after a recap of my EDS computer, it still happened from time to time but more like once or twice a month instead of 3-4 times every time I drove the car. The base mechanical idle is set very low, 450-500 RPM and the EDS solenoid brings it up to ~650-700 RPM. At full extension, the max RPM of the EDS controller is ~1000 RPM.