Mazda3 Forums banner

1 - 20 of 35 Posts

·
Registered
Joined
·
93 Posts
Discussion Starter #1
Hello. I have a 2008 Mazda 3 Hatch, automatic with about 130,000 miles on it. I was having some pretty intense shaking and vibes going on, so I figured it was a motor mount. Just got done swapping all the mounts back to stock type mounts and the shaking is still present. The shaking happens during accleration around 1500 RPM. Let off the gas pedal or go above/below 1500 RPM, the car feels fine. But normally if I'm cruising a city street at 35 or 40 mph, I seem to hit this RPM a lot and it feels like my car is about to shake apart.

What's going on? Is this a misfire, related to a bad ignition coil or something?
 

·
Banned
Joined
·
771 Posts
There is a whole list of questions that would need to be asked.

But the start you need to go to your OBDII diagnostic connector and with a scan tool connected to it check for trouble codes both present and pending.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #3
There is a whole list of questions that would need to be asked.

But the start you need to go to your OBDII diagnostic connector and with a scan tool connected to it check for trouble codes both present and pending.

I didn't think to run a scan tool on it, since I don't have a "check engine" light coming on. But I can try to run by AutoZone today after work and see if they can pull any trouble codes off of it.
 

·
Banned
Joined
·
771 Posts
I didn't think to run a scan tool on it, since I don't have a "check engine" light coming on. But I can try to run by AutoZone today after work and see if they can pull any trouble codes off of it.
It is a misconception that all ECU problems will always generate the yellow caution engine check light. Some time you not only need to review the pending area but the status of the monitors.
If you go to Auto Zone I recommend to have them do the procedure at least twice. NOTE any DTCs that are found for future reference.

For anyone reading this thread...if you own a vehicle manufactured from 1995 to present and plan to try to work on your own vehicle you MUST have the basic Diagnostic Scanning tool to DIRECTLY plug into the on board OBDII/CANbus Diagnostic connector. Without this it is very difficult to find ECU controlled and monitored related issues and properly execute a checking procedure to verify and correct the problem and also for others to suggest a plan for correcting or finding related ECU controlled problems.

 

·
Banned
Joined
·
771 Posts
Ok so than we must assume at least at this point that it is mechanical? The next thing to do is get the car securely and safely up on jack stand and push, pull, rotate, and examine all the suspension and drive train.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #7
@M3RacerX

I can probably get under there tonight and take a look.


I still feel that is something engine related; be it ignition, air, or fuel.....I'm not sure. But I do know the shaking only happens under load/acceleration and at a pretty tight RPM range (1500 to 1600 RPM.) Just feels like the engine is stumbling or bogging down, but once you let off the gas pedal or get out that specific RPM range....the car feels fine.
 

·
Banned
Joined
·
771 Posts
The ECU get all information for engine running and if their is any ignition or fueling will indicate a DTC. If the ECU is not getting the information or their is a problem with the ECU then it will not show a DTC. There are exception and even to this. Also if you did not see a DTC with an ignition issue your monitors will show not in readiness. To read them requires an advanced Diagnostic scanner.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #10
Might be a good idea to note if the Shaking is felt in your Butt in the Seat, through the steering wheel, or through the pedals/floor? Or is just like the whole car at once.
I'm pretty sure it's the whole car. When the shaking is happening, I can't see out of the side view mirrors or the rear view mirror. The dash vibrates too. It can be a pretty intense shaking feeling, but like I said if I let off the gas pedal or get out of that specific RPM range it immediately goes away.
 

·
Registered
Joined
·
297 Posts
I'm pretty sure it's the whole car. When the shaking is happening, I can't see out of the side view mirrors or the rear view mirror. The dash vibrates too. It can be a pretty intense shaking feeling, but like I said if I let off the gas pedal or get out of that specific RPM range it immediately goes away.
Various possibilities.
One thing that stands out with this symptom description is bad inner cv joints. I've seen it multiple times on many different makes and models with this symptom and it was a bad or both bad inner cv joints. The telltale sign on most is leaking grease evident from the inner boots, usually slowly over a long period of time. The loss of grease eventually causes damaging wear in the joint that shows itself on acceleration only, not cruising or coasting, but acceleration or a constant higher than normal torque like maintaining speed up a long interstate grade. Just a thought.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #12
So over the holidays I did get a check engine light. I hooked a code reader up and got a P2187 fault code and P2187 pending code. P2187 is "system too lean at idle (bank 1)".


Sounds like a lot of things can cause this.....vacuum leak, purge solenoid valve, MAF, O2 sensor, etc.


Could this check engine light be related to why car is running horrible and shaking like its about to fall apart?
 

·
Registered
Joined
·
273 Posts
One thing to keep in mind about many codes is that the ECM will require a certain number of reps to occur or time to elapse, before setting the code and turning on the MIL. So it's very possible the pending code is being set repeatedly, whenever the lean condition occurs at that specific RPM. However, because the MIL is not on, you're not aware that's happening. And the pending code doesn't become an actual code, because the lean condition goes away when the RPMs change, and the computer can then erase the pending code from memory. One would think there should be code to recognize the repeating problem condition, but it's also easy to understand how the engineers can't program for every possible issue that might come up.

So I think the answer to your question is very likely yes. Hopefully it won't be too difficult to locate the source of the unmetered air, now that you know what you're looking for.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #14
One thing to keep in mind about many codes is that the ECM will require a certain number of reps to occur or time to elapse, before setting the code and turning on the MIL. So it's very possible the pending code is being set repeatedly, whenever the lean condition occurs at that specific RPM. However, because the MIL is not on, you're not aware that's happening. And the pending code doesn't become an actual code, because the lean condition goes away when the RPMs change, and the computer can then erase the pending code from memory. One would think there should be code to recognize the repeating problem condition, but it's also easy to understand how the engineers can't program for every possible issue that might come up.

So I think the answer to your question is very likely yes. Hopefully it won't be too difficult to locate the source of the unmetered air, now that you know what you're looking for.

With the current symptoms of my car and this code popping up, is there a most likely culprit here?


I'm thinking vacuum leak due to the age of my car. O2 sensors are a maybe due to age as well, but I might do those as a last resort since they can be costly.

I've seen stuff that says this code may be caused by ignition misfire. I guess a bad coil is a maybe as well due to the car's age.

Faulty fuel injectors and bad fuel pressure are also possible culprits too.

I don't think it is Purge Solenoid Valve, since I replaced it maybe 30K-40K miles ago and my car starts up fine after filling the gas tank.
I guess I could clean the MAF and the Throttle Body and see if that helps with anything too. It's been bitterly cold lately, but it's supposed to be nice this weekend so I will take a look then.
 

·
Registered
Joined
·
273 Posts
Here's one good write up on finding vacuum leaks, but you can find many other similar ones as well. I particularly like what they say about safety precautions, because that is really the most important thing IMO. I'd prefer to test using the vacuum gauge before getting into spraying the carb cleaner, but that's a minor consideration, and not meant to be critical of what they've presented.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
 

·
Registered
Joined
·
93 Posts
Discussion Starter #16
Here's one good write up on finding vacuum leaks, but you can find many other similar ones as well. I particularly like what they say about safety precautions, because that is really the most important thing IMO. I'd prefer to test using the vacuum gauge before getting into spraying the carb cleaner, but that's a minor consideration, and not meant to be critical of what they've presented.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
Sprayed every hose I could today with carb cleaner. Engine never revved up though. Inspected all hoses for cracks and holes too.....so I guess no vacuum leaks?

I cleaned the MAF and throttle body plate also. No change in the problem. It's still there. I did notice the gasket on the MAF was a bit stretched out though. So I'm going to try to get a replacement of one of those.

Any other ideas?

I'm going to borrow a more robust ODB2 scanner from a friend tonight and hook it up and see if it gives me anymore info or leads.
 

·
Registered
Joined
·
483 Posts
With the current symptoms of my car and this code popping up, is there a most likely culprit here?


I'm thinking vacuum leak due to the age of my car. O2 sensors are a maybe due to age as well, but I might do those as a last resort since they can be costly.

I've seen stuff that says this code may be caused by ignition misfire. I guess a bad coil is a maybe as well due to the car's age.

Faulty fuel injectors and bad fuel pressure are also possible culprits too.

I don't think it is Purge Solenoid Valve, since I replaced it maybe 30K-40K miles ago and my car starts up fine after filling the gas tank.
I guess I could clean the MAF and the Throttle Body and see if that helps with anything too. It's been bitterly cold lately, but it's supposed to be nice this weekend so I will take a look then.
Just FYI: The O2 sensors should be replaced about every 75K miles regardless of throwing a code or not. They degrade in performance over time, so replacing them helps keep the emissions system in peak operating condition. O2 sensors which operate at peak efficiency ensure the catalytic converter will never have to be replaced (which it shouldn't unless there was a manufacturing defect).

A misfire could be due to worn insulation at the coil pack harness; a cracked coil pack; bad valve; or, a bad spark plug.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #18 (Edited)
Just FYI: The O2 sensors should be replaced about every 75K miles regardless of throwing a code or not. They degrade in performance over time, so replacing them helps keep the emissions system in peak operating condition. O2 sensors which operate at peak efficiency ensure the catalytic converter will never have to be replaced (which it shouldn't unless there was a manufacturing defect).

A misfire could be due to worn insulation at the coil pack harness; a cracked coil pack; bad valve; or, a bad spark plug.
I'm now getting a bit of vibration and shudder when I first accelerate from a stop. The shaking isn't as bad as it is around the 1500 RPM mark, but it's there and it didn't used to do that.

Is there a way to test the O2 sensors, before shelling out the cash to get new ones? I heard of people unplugging the sensors and seeing if that improves issues or makes them worse.
 

·
Registered
Joined
·
93 Posts
Discussion Starter #19
Would a video of the issue help?

I'm pretty sure the shaking and vibration is loud enough to be picked up on cell phone video.

I will try and take one in the next day or so.
 

·
Registered
Joined
·
483 Posts
I'm now getting a bit of vibration and shudder when I first accelerate from a stop. The shaking isn't as bad as it is around the 1500 RPM mark, but it's there and it didn't used to do that.

Is there a way to test the O2 sensors, before shelling out the cash to get new ones? I heard of people unplugging the sensors and seeing if that improves issues or makes them worse.
If you've never replaced the O2 sensors and your vehicle has over 75K miles, I'd say it's safe to go ahead and replace them anyway.

Are you getting any codes?
 
1 - 20 of 35 Posts
Top