I believe it is behind the engine on the firewall. It is a single wire and connection that breaks out of the main harness.
According to the repair manual that I am reading, you do not have a distributor, you have coil packs (3). There is not a vacuum advance persay. The spark advance is caused by the vehicle computer.
10 degrees advance
84 has a vacuum advance 89 has an electronic advance Thats the only diff.
Counter clockwise to advance.......clockwise to retard
To remove the distributor on a 1997 Chevy Tahoe, first disconnect the negative battery cable to ensure safety. Then, mark the position of the distributor and the rotor to aid in proper reinstallation. Remove any wiring harnesses and the vacuum advance line, then unbolt the distributor hold-down clamp and carefully lift the distributor out of the engine. Be sure to note the orientation of the rotor as it turns when you remove the distributor to ensure correct timing upon reinstallation.
Rtr. turning clockwise. Rotate distributor counter clockwise to advance timing, clockwise to retard.
it does not have a distributor , it has coil packs
you need to disconnect the electronic advance plug on the side of distributor and aim the timing light on the pointer and move distrbutor until the nuber is right,usually 4 or 8 degrees
Turn it to the opposite direction that the rotor rotates.
If that vehicle has the 2.2L engine, it doesn't have a distributor.
Loosen the bolt holding the distributor in place, and turn the distributor counter clockwise. If it bucks the starter, it is too far advanced.
It is inside the distributor