Originally the car would stall and die. I replaced the O2 sensor, fuel pump and filter, IAC Valve, Oil pressure sensor, and oil sending unit. Now the car is acting up worse than ever and displaying ECM data link problem. Any suggestions as to what might be causing this problem?

The ECM itself may be bad. Consider installing an exact part no. match.

Ok the car is no longer displaying the ecm error and is now back to its original issue of dying randomly whether it is idling or being driven. Any suggestions as to what else could be causing it to die like that? We have also checked for vaccuum leaks and there are none and its not showing any codes at all when scanned.

Replace the Ignition Control Module (ICM). Easy job.