Have you tried blanking the computer?, on my car it is located on the firewall about 6 inches inboard of the battery. disconnect the ground cable on the battery and carefully remove the ECU from the harness. leave the ECU disconnected for about an hour, this will allow the capacitors in the ECU to completely discharge and thereby erase any memory that may be stored onboard the ECU it wont however erase the hard-coded engine profile and operating data that the computer uses for engine managment. as a result of losing the volatile memory that the computer stored from data received from various engine sensors you may have poor drivability until the computer can rebuild its custom engine operating profile.

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1984
190e 2.3L
107000 miles