Replacing the Sparks Plugs...

[4wardmotion]

Coming up on 50K miles and want to replace my plugs as part of routine maintenance, as well as to see if new plugs will eliminate the occasional hesitation I'm getting while driving on the highway.

Has anyone here performed this replacement yet?

If so, please let me know how difficult it is to get to all plugs.....any special tools needed? I'm a 'Saturday Mechanic' at best, so any helpful tips would be appreciated.

Thanks!

 

[mazdaspeedster3]

Your plugs should be good well past 50K. More like 100k if then... If you are hell bent on changing them though I guess have at it. You probably just need to take the plastic engine cover off the top and you will see your 6 plugs.

 

[ceric]

...eliminate the occasional hesitation I'm getting while driving on the highway.

That could be from the transmission logic from learning your driving style.
To overcome it, I usually use shift to manumatic mode (+/- gear) to get the exact gear I need. It could also be the infamous faulty throttle body is acting up on your CX9. It depends on the symptoms you experienced.

The plugs on CX9 are not required to be replaced (platinum tipped) until at least 100K, and they are expensive (OE price >$20 each) to replace.

 

[SeCX-9]

Ceric, do you have the TSB for this throttle body issue?

 

[ceric]

Ceric, do you have the TSB for this throttle body issue?

SeCX-9,
I don't think there is one yet.
I have not found a single site that contains all the CX9 TSBs. The best solution is to watch several sites. I can offer two below. Together, it is very complete.

(1) http://www.finishlineperformance.com/store/pages.php?pageid=15
(2)
http://www.ford-trucks.com/tsb/tsb.php/m-MAZDA/y-2007/d-CX-9
http://www.ford-trucks.com/tsb/tsb.php/m-MAZDA/y-2008/d-CX-9
http://www.ford-trucks.com/tsb/tsb.php/m-MAZDA/y-2009/d-CX-9

 

[todd92]

No way you need spark plugs at 50k miles.

 

[badself]

One more vote that plugs aren't your problem.

If you're going down the highway and your rpm's are surging and dropping 200-300 prm at reliable intervals (maybe 10-25 seconds), you probably have a defective throttle body. I can see somebody describing that as a miss. Is the truck having trouble keeping a smooth idle with the air conditioning on, or cutting out at a red light? These are all symptoms of the throttle body problem.

I don't suggest going in and changing plugs until you have the dealer document your problem. They could very well say your "miss" is the result of the replacement plugs or your work. Make them call Mazda about the throttle body, especially in they're telling you "no trouble found". Mazda is fully aware of the problem, but ultimately proving it will be on you. Not impossible, but it may take persistence.

Good luck.

 

[4wardmotion]

Thanks everyone.

I (sort of) miss-read the maintenance section of the OM. Schedule 2 states to change the Plugs at 60K miles. Schedule 1 is 100K. Not exactly sure which schedule I should follow since there are some references to using Schedule 2 that do apply for me.

I guess I was trying to avoid having the dealer replace the plugs for (say, $200) to correct my issue, when I could probably do it myself for 1/3 the cost. Although I don't think the issue is my plugs, I was going to replace them just to eliminate that as a potential cause.

My description of a 'hesitation' isn't exactly accurate. It always happens when I'm on the highway, usually using Cruise Control. The condition is quick and momentary....like the car just lost fuel for a split second. I get a brief stuttering / vibration that I can fell in the pedal and before I can even glance at the Tach, it's over and back to normal. I can't even be sure it's not the tranny, but I don't think it's a case of it down-shifting and then up-shifting that quickly.

I thought it might be a bad tank of gas, but I filled up at a different station after adding both Dry-Gas and Fuel System Cleaner (and used Premium Gas too) but the condition has continued, although the frequency doesn't seem as bad as before.

I'll have to look into the issue related to the Throttle Body as you mentioned above. Could it be a dirty Fuel Filter? I haven't changed it yet, and I think that might be due soon...or over-due...I'll have to check.

Thanks.

 

[ceric]

I don't think there is a schedule to change fuel filter per maintenance.
Schedule II is for people frequently drive short trips, tow heavy load, on tough terrains, or in dirty air environment. Most drivers do not fall into that category.

Could it be the cruise control losing vacuum for a split second?
Were you always on cruise control when that happened?

 

[badself]

After reading your second description of the issue, I'm 99% sure you have a bad throttle body.

It would be nice if Mazda stepped up to the plate and released the appropriate TSB.

It would be even nicer if our cars were not so heavy on Ford components.

 

[4wardmotion]

Ceric - it's not always when using CC. In fact, it happened to me again today a couple of times....and both times I did not have the CC engaged.

What is interesting is - I believe at least some (most?) of the times that I have noticed this happening is when I am starting up a hill, but not a drastic incline. I don't think the car is down-shifting - I just feel a slight 'jolt' and the car 'hiccups'.

badself - I called my local Mazda dealership about this - although I've not been very impressed with them anytime I do business with them. So far, after saying they would check Mazda's service notes about the Throttle Body, they said they couldn't find anything related to the Throttle Body.

I might try a different dealership tomorrow. Would the Throttle Body be covered under the 5/60 warranty?

 

[ceric]

In my opinion, it could be one of the two things
- throttle body
- pedal position sensor
However, since throttle body is a known issue with CX9, I will vote for it also.
It should be covered by 5yr/60K powertrain warranty, in my opinion.
(example: GM's Powertrain coverage: http://www.proaxis.com/~randyjones/PowerTrain.html)

Make sure you visit a Mazda dealer by 60K miles and ask them to make a note of the fact that you
report this problem before 60K. You need this because if the problem gets worse and
identified later beyond 60K, you still can ask Mazda to cover it since you report it BEFORE 50K.

 

[4wardmotion]

Thanks Ceric!

I'll have them check it...but with it happening so infrequently, I worry that they'll waste my time and multiple visits before they ever figure it out. But you're right, I should at least have them document the concern for potential issues down the road.

 

[badself]

4wardmotion,

Best thing to do is ask the dealer to call "Mazda Techline" for feedback on your problem. Most of these Mazda dealers won't even go that far for you. Then you have the infrequency issue, which makes it hard to confirm the issue to Mazda's satisfaction.

Mazda Corporate has more than several completed warranty claims related to CX-9 and throttle body defect. If you can open a claim, eventually they may do the work even without confirmation of the symptom.

Maybe ask the service manager to take a ride with you (possible an extended ride). Most of the time with my issues, they haven't even been gracious enough to do that. Anyway, ask the service manager to keep an eye on your tach as you're driving up a slight incline. The tach will hiccup at the same time as the rest of the car. It's not going to be easy, but you deserve to have a car that's running normally, basically what you paid for and what warranty is designed to give you. If you stay on it, I can't see you not getting a resolution.

 

[4wardmotion]

Thanks badself.
I only have about 4 or 5 months left on my powertrain warranty - I should hit the 60K mark sometime just after the first of the year, so I need to get this addressed soon.

I've got another 8 hour trip on Monday and I'm hoping to eliminate the tranny as a possible cause. Today, while driving on the highway, it happened a couple of times....and then it dawned on me that when I'm cruising on the highway, I should switch it over to Manual to 'lock' it into 6th Gear. I actually did that today and it never hiccuped again....so I'm still not completely convinced that it's not the tranny doing a quick shift down/up but I should be able to verify that on Monday since it almost always happens a couple of times per long trip.

Thanks again for your feedback / recommendations!

 

[4wardmotion]

This is sounding more and more like normal 'hunting' when you're on the cusp of which gear is best. Is this your first 6 speed auto? More gears, more frequent possibilities to change gears.

On undulating roads I always use manual to keep it in 5th. This also helps the cruise maintain speed up, and down, hills.

I believe this is the first 6-sp auto I've had. But, as I approach 50K miles on the odo and 2 years of ownership, this isn't something I've been experiencing until recently.

Today, during a 435 mile round trip from MA to NH (lots of hills) I experienced this same issue frequently. But not once did it occur while switched over to Manual Mode in 6th gear, and I tried to keep it in 6th as much as possible.
I'm beginning to think it's a tranny issue after all.....(sad2)

 

[tstex]

Guys,

Have an 09 CX9 GT...is the suspect throttle body issue indicative of all CX9's or specific years?

Thank you very much,
tstex

 

[ceric]

My understanding is that it is more like a higher-defective rate part.
It enough people complain about it on NHTSA website, it will become a case to investigate.
Then, it could potentially become a recall (since it is safety related - loss of power on highways is always a safety issue to me).
However, there seems to be not enough cases so far.
If Mazda thinks that this problem is hard to identify, they will issue a TSB. TSB does not always associate with a VIN range.
Sometimes, it merely tells mechanics what to do and how to identify, and what parts to order.

No. the throttle body problem is due to defective parts from Ford. I hope the running change makes the later ones better.

 

[Lindyrect]

Anyone try these yet?

http://www.pulstar.com/

 

[ceric]

Sounds great but don't try it before your 5yr/60miles warranty expires. Just my suggestion.
If anything goes wrong that can be traced back to the plugs, warranty will be voided.

I doubt about the 10% MPG improvement, though. Maybe 1-2% gain at most.
Using a Prius as example is wrong (I own one). Prius is very very very sensitive to driving style.
You mood in the commute can change MPG by more than 20%!!!

Again, if that is true, every automaker will have it as OE parts. Why direct injection?! This plug gives you 10% improvement.
That is why I have my doubt. However, if I need new plugs and my powertrain warranty is out, I might try it.
$15 a piece is reasonable.
Remember the now-old Y plug (which also claimed to improve MPG...). Why is it not very common now?
A lot of marketing hype.