After replacing the spark plugs, coils, wires,and using Sea Foam Spray and Chevron Techron Fuel Injector Cleaner the engine started dying at idle rpm with Check Engine Light. OBD II says P0171. What starts out simple gets complex, all pods get knocked off course.

Decided to perform a 60K Mile Maintenance that includes new fuel injectors and a new fuel Pump, new tires, rotors, and pads, all new fluids, air conditioning recharge and fuel/vacuum gauge troubleshooting. The detailed steps and diagrams are included in the following post. Found the primary fuel injectors clogged and the fuel line losing pressure with ignition off.

 

The following topics are covered in the attached PDF:

DIY Detailed Tools, Fluids, and Parts for 60K Maintenance with Cost and Links
DIY Mazda RX8 2005 Series 1 Automatic Sport Suspension 60K Maintenance
DIY RX8 2005 Series 1 60K Maintenance Notes
DIY Engine and Differential Oils and Filter Remove and Replace
DIY Rotor and Brakes Remove and Replace
DIY Brake Fluid Remove and Replace
DIY Headlight Restoration
DIY Coils, Spark Plugs, Spark Plug Wires Remove and Replace
DIY Check Engine Fault Code P0171 and P2096 Troubleshoot
DIY Fuel Pump Remove and Replace
DIY 2005 RX8 4-Port Automatic Fuel Injectors Remove & Replace
DIY Fuel Hoses, Quick Connectors, Fuel Pressure Gauge, Vacuum Pressure Gauge
DIY RX8 2005 Mazda M3 D3 4 Speed Automatic Transmission Fluid Maintenance
DIY Air Conditioner Charging
OBD II/Torque Pro/Smart Phone
Isolating Problems Through Fuel Pressure and Vacuum Measurements
Mazda RX8 2004-2008 Section 1300A 02/03 Inlet Manifold (AT) (UIMU – UIML)

Symptoms:
Slight Rough Idle, Slight Hesitations at Higher RPM, Longer Starts after Warm-up

 

That's a helluva useful document there Guy!

 

When you measured the inlet vacuum, which side of the on-way valve in the brake booster line did you connect to? I suspect that you were on the booster side from the lack of drop off. I measured from the manifold side of the valve and it returns to atmospheric pressure on stopping the engine.

 

Update 11/01/2017: The added High Pressure Fuel Injection filter blew out.
Update 11/11/2017: The Gates Hose with Double Clamp Method Failed.
Updated PDF to reflect these fuel hose issues.

 

Update 11/18/2017: The Gates Fuel Line with Double Clamp Method Failed. The RX8 Club states the fuel line needs 7 mm I.D., the 5/16” Gates fuel line is 7.94 mm I.D. The Gates hose with double clamps failed within six months. The new 49XB fuel line arrived. The 49XB has been upgraded from the original 49X design. A checker tab is integrated with the quick release connector for all of the new fuel lines. The checker tab releases from the quick release connector after it is completely engaged. This situation started with the need to measure fuel pressure, the Mazda tool was expensive, cut fuel line, should have bought the tool.