Car struggles to idle without stalling

GMFan

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JC1

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Did you check the Mazda forums?

How long has it been since you did all the work? As that guys video says idle the car with no ac and no radio on for 15-20 mins. Then idle the car for 15-20 mins with Ac on. I would give that a try. Nothing to lose at this point.
 

GMFan

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Did you check the Mazda forums?

How long has it been since you did all the work? As that guys video says idle the car with no ac and no radio on for 15-20 mins. Then idle the car for 15-20 mins with Ac on. I would give that a try. Nothing to lose at this point.
Battery about 1 month ago, MAF one week ago. Trying the idle relearn now. Nothing to lose..
 
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Based on what you have checked and everything I can say it’s most likely the fuel pump or fuel filter because my Mazda done the same running horrible, bucking, jerking surging type of deal and I replaced the fuel pump and it was fixed then I replaced the fuel filter because I figured it would help too which it did.
 
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Astro14

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With this many miles, I would check the throttle body itself.

A couple of things can happen, first, you can get oil/carbon build up that causes rough idling and poor part throttle performance. So, I would check, and likely clean, the TB. Soft nylon toothbrush and plenty of solvent with the body off the car. Get a new gasket to put it back on the manifold.

Next, the actual sensor (throttle position sensor, essentially) and the actuator (which moves the throttle) can simply wear out with time. Depends how it’s built, but a worn out TB is a possibility. To check that, you need Mazda-specific diagnostic tools that can “sweep” the body, that is, run it from full closed to full open, and check the readings.

Don’t go throwing parts at this. Clean the body first. Perhaps you’ll get lucky and that’ll the the problem.

Then, if that doesn’t work, you need to check fuel pressure, do a throttle body sweep, etc... proposer diagnosis with proper tools. Too many possibilities to just fire up the parts cannon and hope you hit the target.
 
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I hope this helps


my 08mazda6 had the same issue or better say roughly the same; any time I would disconnect negative off its battery, next start it would run "roughly" for about 5 days, then the things would go back to normalcy


milage at the moment
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GMFan

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New symptom I noticed. The issue seems to happen when the AC is being used. When the AC is running it seems the engine RPMs are dropping too low. Would this point to a particular sensor? RPMs much more “normal” when the AC is off. The fan blower running doesn’t seem to be an issue either, just when the AC is on.

FYI I did the idle relearn procedure and it seems better but hard to say as I only drove the car a little bit today. Whatever the issue is it is intermittent and sometimes not very noticeable.
 
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GMFan

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This morning it was very cold and I started the car up and immediately the RPMs were idling at 2000. Then on way to work the car was running so poorly it was almost undriveable. Id let off the gas and the car seemed to still accelerate like it had throttle, realize I had let off the gas and then it would buck and engine break really hard. It also had horrible acceleration. I’d lightly touch the throttle and the car RPMs would way overreact like I was flooring it.

I gave up and made appointment with the dealer to diagnose the issue. Will report back with what they find.
 

GMFan

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The dealership diagnosed the issue as a dirty throttle body and dirty fuel injectors and carbon buildup in the manifold. They did an EFI service (Mazda’s version of sea foam), and some sort of fuel injection service, and a fuel additive and the car runs like new. Car feels like it has 50 more HP, idles quieter, accelerates smoother and runs great. I’m surprised but glad it seems fixed!
 
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