I have a 90 d21 pickup 4x4 with v6 that shuts off when the motor hits 2200 rpms then recovers after the tach drops down to 1000rpms. It runs flawlessly as long as you dont rev it up to 2200. I've replaced the ECU and the air flow meter and seemed to be fixed then it started the same old stuff. I checked the spark when it cuts out and the spark stays on. Does anyone have any ideas. HELP!