2000 GMC Jimmy 4x4
One of my friends has a Jeep and in his stock key fob he hits lock unlock lock, and it starts. Im thinking of sending out my PCM to have it tuned, and i was wondering if something like that can be programed into mine when they tune it?

 

I do not believe that the function you have described is something that can be programmed into the PCM. The RKE (remote keyless entry) module talks with the BCM (body control module), not the PCM. If it were possible, you would need to reprogram all three for the capability. GM never offered factory remote start on these trucks which is why I do not think it is a possibility.

Your best bet would be to go with an aftermarket remote start kit which will come with a new keyfob; most of the time with better range & capabilities.