Hello and thanks for using Just Answer.I will try my best to help you with your question.
The lean codes are most likely caused by a vacuum leak. Inspect the PCV hoses from the passenger side valve cover to the back of the engine. Make sure the rubber elbows are not soft and sticky or collapsed together. Oil in the system causes the hoses to fail and break down causing lean codes like yours. Check and repair any PCV hoses and then clear the codes.
The MAF will not cause a no start and no fuel pressure.
There is a test port located on the fuel rails for the fuel injectors. The test port is on the passenger side of the engine on the intake manifold back behind the heater hoses. Push the needle valve down and see if you get a BIG spray of fuel. If not, you more than likely have a failed fuel pump.
No power at the inertia switch means either a fuse of the relay.
The fuse is #19 a 20 amp fuse under the hood in the engine bay fuse box. The relay is located under the dash next to the steering column on the passenger side of the steering column.
Sorry about that, my diagram from the factory shop manual shows it under the dash to the right of the steering column.
The black fuse like plugs are Diodes. They absorb voltage spikes in the circuits.
Below are the wiring diagrams for both diodes.