Is there an easy way to disable a PK3 security system on a 2000 Grand Prix:2cents:

Welcome Aboard!

No. The BCM communicates with the PCM based on a signal from the lock cylinder. If you can reprogram the PCM, that would be an "easy" way around it. Without the signals, the PCM will not operate the injectors.

Why would you need to do this? Are you stealing a car? Or do you just want to buy cheap keys? www.streetkeys.com has a pk3 key for your car for only 15.00 and it comes with programming instruction. The dealer should be able to cut it for free.