My 1997 GLE with 195K miles was running fine until about 2 weeks ago. At first it was just hesitation when accelerating, which became stalling when starting or driving and now it won't start at all. I thought the problem must be a worn out ignition coil, so I drove the car to Autozone to be scanned to find out which cylinder had the issue. Autozone said the resulting code was P0105, which they said means the ECM (engine control module) needs to be replaced. A mechanic I know said the code number is wrong and the problem may not be the ECM.
Any insights you guys may have regarding this problem would be greatly appreciated!

Did you research anything?

Investigate the Map/Baro system. INCLUDING the vacuum hoses. 26 year old hoses do split and leak, and the 195K miles means the sensors and switches owe you nothing at this point.

Many have done a complete Intake Refresh at this point! Most get their cars running almost like new.

Did the mechanic you know let you know what correct DTC is?

If so, what is it?

If not, that’d be a good starting point.