Power train system, how to fix a code p0 102?

Hello, most likely on a vehicle this age the MAF has some carbon or dirt built up on the inside of the sensor, you can verify 12volts on the pink wire, which is the power feed, black/white wire is Ground, Ill post a wiring diagram. Just to be sure you have good power and ground to the sensor. I'm sure it's just an old sensor.
You can try some MAF sensor cleaning spray, they sell it at most auto parts stores.

But also, any air entering the engine past the MAF is considered to be false air that the ECM is not calculating for because it's not able to read it. So, any vacuum leaks into the Intake manifold, or loose hose clamps on the air intake boot will not be read by the sensor.
If you have a scan tool that can read live engine data you can check the grams per second (g/s) at idle, it should be 5-7g/s according to service info. They can be difficult to see inside, but don't use anything else besides MAF cleaner if you try to clean it.

Another thing to keep in mind, if you happen to find carbon build up on the throttle plates, it's time to replace the PCV valve as well. A sticking PCV valve is the first thing that will cause carbon build up everywhere. This vehicle has a lot of mileage so sensors by now are going to be slow in response time. Thats just normal wear.
It might just be time to replace the sensor if you find that it's really bad inside.
I'll post some extra service info for you.