Fuel Pump Replacement? - 2007 CX-9 Sport

So - I've had this issue for a little while. I used to get a CEL and had it pulled at Auto Zone - lean condition came back. All signs (google searches) point to low voltage on the fuel pump, which is restricting fuel flow at times, and every once in a while, the engine will cut out. It will however start right back up without issue. The only way I've really been able to "get around" this issue is to run the A/C on auto all the time so that the computer kicks up the fuel on idle when the compressor turns on, which will prevent the engine from cutting out.

What I'm wondering is, how hard is it going to be to replace the fuel pump myself. Does this sound like it could fix the issue? I'm no novice at auto repair, however, I'm no expert either. Can anyone give me some guidance here? I'd like to avoid going to the dealership if at all possible.

Thanks in advance!

The fuel pump is right on top of the fuel tank.
I haven't heard anyone DIY it.
Yes, it sounds like it could be the culprit.

I would wire in a volt meter that you can watch and see if the voltage going to the pump is the problem. This won't tell you if he pimp stops working though but reading amp draw on the particular lines should.

You can also hook up a fuel pressure gauge to see if the pressure is dropping when it happens. I don't have enough experience under the hood though to tell you if there is a port you can hook into.

How many miles are on the car?
What was the code it was throwing?
Was it a lean code for all cylinders (both banks)?
Does happen more when the engine is cold versus warmed up? In warm or cold weather?
Does it seem to run fine and have plenty of power above idle?

I'm not that familiar with the CX-9, but most traditional fuel injections systems run the pump at one speed all the time. The pressure is regulated by a pressure regulator. So while there could be a problem with the power getting to the pump, it seems like one of the less likely causes of your problem. If you turn on the AC, then engine is slightly increasing the air flow through the idle control valve. I really doubt there is any change in voltage going to your fuel pump. I'm guessing that increase airflow is what is keeping it from stalling.

I would be suspect of the Idle Air Control Valve. These commonly get dirty and gooked up crud... especially on higher mileage vehicles. They can be taken off and cleaned or, there are products like seafoam that you can run through the the intake while running that are designed to clean them out.

Also, the throttle body itself is known to have some issues on these early models. Below are a couple of links with Throttle Body issues.

Uneven Idle

Mazda CX-9 Stalling

Other thoughts that come to mind would be

Fuel contaminants / clogging fuel filter / fuel pickup
Vacuum Leaks

You might want to check the connector at the fuel pump / fuel tank to make sure it's secure and has good connections. I would do some more troubleshooting before I pulled the trigger on a new fuel pump.

I'll chime in on searches I've done on the forum for this topic. It seems that most Mazdas, (and I would assume most cars) have an access port to get to the fuel pump/regulator that is inside the car, under some carpet and a steel plate. This was the case for the RX-8, Protege, and MX-5 pictures I've found. No specific pictures to the CX-9 though.

Good idea on checking the TB or Idle Control Valve @Scotch3. TB plates are known to get gunked up a little bit at the edges, preventing proper operation. The "Goss Garage" explanation, good info here: After the video, Youtube suggests a bunch of useful videos for it as well.

https://www.youtube.com/watch?v=XrcaDh4xDLs