P2178, P2004, P2188

[LinkinEffect]

Title says it all, 3 new CELs.
I figured a good place to start is the O2 sensors. But which one? Upstream?

What do you guys recommend?

Reference:
P2178 System Too Rich Off Idle Bank 1
https://www.obd-codes.com/p2178
P2004 Intake Manifold Runner Control Stuck Open Bank 1
https://www.obd-codes.com/p2004
P2188 System Too Rich Off Idle Bank 1
https://www.obd-codes.com/p2188

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[Galaxy771]

Currently having the 2188 issue but from what I read, you're having 3 separate CELs at the same time? All of these combined kinda looks like it might be something a little easier than my current issue. First thing, check the PCV valve to see if it's stuck open or stuck closed because that is an easy enough test to do and not expensive to replace. Second get some kind of ECU reader to check the readings of your upstream(bank 1 sensor 1) O2 sensor because that might be bad, after that check for leaks by your injectors.

If you ask me personally though it seems like the problem is near the intake manifold, such as the PCV or something like that just based off your second code. My reasoning being if a runner is somehow constantly getting air then it would explain the increase and richness of fuel. More air means more fuel so it doesn't run lean right? Another thing to check is intake manifold pressure and check for leaks as well near your manifold or intake.

Another possibility although unlikely could be that your throttle body plate is stuck and if that's the case just give it a really good cleaning with the appropriate cleaner and make sure everything is clean and kosher. Clean the MAF while your at it and while you have that off check the MAF wires.

Hope this all helps and if you find a fix, let me know.

[LinkinEffect]

Currently having the 2188 issue but from what I read, you're having 3 separate CELs at the same time? All of these combined kinda looks like it might be something a little easier than my current issue. First thing, check the PCV valve to see if it's stuck open or stuck closed because that is an easy enough test to do and not expensive to replace. Second get some kind of ECU reader to check the readings of your upstream(bank 1 sensor 1) O2 sensor because that might be bad, after that check for leaks by your injectors.

If you ask me personally though it seems like the problem is near the intake manifold, such as the PCV or something like that just based off your second code. My reasoning being if a runner is somehow constantly getting air then it would explain the increase and richness of fuel. More air means more fuel so it doesn't run lean right? Another thing to check is intake manifold pressure and check for leaks as well near your manifold or intake.

Another possibility although unlikely could be that your throttle body plate is stuck and if that's the case just give it a really good cleaning with the appropriate cleaner and make sure everything is clean and kosher. Clean the MAF while your at it and while you have that off check the MAF wires.

Hope this all helps and if you find a fix, let me know.

I went along and did what I said I was going to do first, changed the upstream o2 sensor. Only CEL left after an hour of driving is P2004. (And my thermostat needing replacement, but that's obvious.)

Although, I have FIVE pending CELs now. Listed below.

P0128
P0421
P2004
P2178
P2188

Still running rich, and downstream O2 is going to be replaced later this week. First cat is built into the header, so I really don't want to replace it haha. But it is what it is.

New recommendations? As for the pcv valve, I'll look into it's cost and how to replace it.

Thank you for the reply.

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[morganc]

The PCV is cheap, but is awful to get at. You have to remove the whole intake plenum. It took me 4 hours.

[LinkinEffect]

The PCV is cheap, but is awful to get at. You have to remove the whole intake plenum. It took me 4 hours.

That sounds lovely. Looks like there is plenty of things in the way for removal. But. Four hours in my garage is alot of saved money.

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[Derek195]

I had the same codes in my 2004 Mazda 3 Sedan GS. The car would run rough at idle, then adventually stall itself out. What I did was go to Wal-mart, or an auto supply store near you and get a can of throttle body cleaner. What I did to take care of the problem was; unplug the battery from the car, take off the throttle body, clean the throttle body flap, then re-assemble. Heres a video explaining it https://www.youtube.com/watch?v=75I24szhsco and heres a link on the forum of what people have been doing http://www.torontomazda3.ca/forum/sh...-Body-Cleaning. I hope this helps!

[Galaxy771]

I would seriously consider finding some tool to use so you can see your car readings in real time and see what is currently out of whack. LTFTs, STFTs, intake manifold pressure, etc...

I currently have a bluetooth obd2 plug-in with the torque app which all-in-all cost me less than $15 and it gives me consistent and solid readings so I would go that route at the very least just so you can see more current and consistent readings.

Find out what's going out of whack first and by process of elimination find something that connects them all so you can find the root of your issue.

[LinkinEffect]

I would seriously consider finding some tool to use so you can see your car readings in real time and see what is currently out of whack. LTFTs, STFTs, intake manifold pressure, etc...

I currently have a bluetooth obd2 plug-in with the torque app which all-in-all cost me less than $15 and it gives me consistent and solid readings so I would go that route at the very least just so you can see more current and consistent readings.

Find out what's going out of whack first and by process of elimination find something that connects them all so you can find the root of your issue.

I do have one, but I don't exactly know what's reading incorrect and what's not. As I have no idea what it should be reading.

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[LinkinEffect]

I had the same codes in my 2004 Mazda 3 Sedan GS. The car would run rough at idle, then adventually stall itself out. What I did was go to Wal-mart, or an auto supply store near you and get a can of throttle body cleaner. What I did to take care of the problem was; unplug the battery from the car, take off the throttle body, clean the throttle body flap, then re-assemble. Heres a video explaining it https://www.youtube.com/watch?v=75I24szhsco and heres a link on the forum of what people have been doing http://www.torontomazda3.ca/forum/sh...-Body-Cleaning. I hope this helps!

I shall give this a try, thank you!

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[Derek195]

I shall give this a try, thank you!

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You're welcome! Just take your time at it. Best of luck!


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