Is this the same problem as the Passlock??
 

Hi, I've got a 99 Alero 2.4 which my mechanic tells me has the anti theft system trying to activate while the car is running. When the car is first started the horn will beep after a minute. The shifting is rough and the car will die going around corners if you don't two foot it. He read me the codes and explained that it would appear the system is trying to arm itself while I'm driving. My question is would disabling the passlock(cutting the thin yellow wire) help me with my problem?? Any help would be appreciated.

What codes did he give you? Post the numbers please.
This doesn't sound like Passlock to me, but doing the bypass won't hurt. See the sticky at the top of the Alero section.