Hi,

I have a 2003 mazda 6 s with 80k and it's been fine until this past week, on tuesday I started it up and it was driving very rough and I took to autoshop right away I use and they found the air intake hose was cracked. They did computer diags and didn't find anything else, replaced air intake hose and it is running better but the check engine light still on.

Took it back to shop and they looked it over some more and didn't find anything else and told me to drive it around for a day and come back. I did that and noticed the car wasn't running well at higher RPMs like it was missing a cylinder, etc. So took it to the mazda dealer and they found that 2 of the 3 rear cylinder coils were bad and needed to be replaced. I replaced all 3 in the rear since they had it opened up. Now waiting on new rear catalytic converter which they say also needs replaced.

But even after getting the coils replaced, my car doesn't seem to be running the same as before. Maybe after the cat is replaced it will be?

Why would all this go bad at once? It did rain good the night before these problems but my car has been out in bad weather before.

Any ideas? I already have 2100 into the car this week.

 

I would suggest you check your PCV valve. If you are replacing your cat because of internal problems it could be because of of oil getting sucked through a bad PCV. Check the threads for the procedure if you are not sure. This is DIY so you dont have to take it to the shop. Also if you get the valve from autozone they have the wrong part number so you will get the wrong valve.

 

if the any of the cats are bad or even slightly clogged the car will lose a ton of power and run like poop

 

I have a 2004 Mazda 6s. For about the last three years, most times I would leave my car in a parking lot overnight in the rain, I would have severe "hesitation" in the engine the next day. I've taken the car to the Mazda dealer on multiple occasions to resolve this. I've had all 6 ignition coils replaced (twice), injectors cleaned, plugs replaced, etc. This would temporarily eliminate the symptoms...until the next time I would leave my car outside overnight. The issue codes usually referred back to the catalytic converter, O2 sensors, and cylinder misfire.

Until this week, a bottle of HEET would usually eliminate the hesitation on acceleration whenever I would have this problem. However, this quick fix is no longer working.

I took my car into Mazda, and they replaced cylinder 5 ignition coil and spark plug. They told me this issue will most likely come back unless I replace the catalytic converter ($1500).

erickbe, I'm interested to know if you were able to get this issue resolved on your car? In some other forums, I saw that this is a pretty wide-spread issue on Mazda 6s. Has Mazda done anything to resolve this? Is there a class-action suit out there?

 

Welcome to the forums!! I REALLY doubt your going to get a reply from erickbe since that was his one and only post way back in 2011, you would be much better off starting a brand new thread and not bringing dead ones back to the top. I know one of the Mazda6 guys will pop on here soon and give some good insight

 

Wow, i just pressed the wrong button again by accident. This time no copy and pasting. Sorry for the late insight!
Yes Driving around with misfires for as long as you have (Ramal17) will screw up your CAT.

READ: How can I tell if my catalytic converter is... — Yahoo! Autos

Wasted 30 minutes on screwing up on my end. Oh well. Things I do to help!

Cats fail from improper maintenance mainly.

Another question------WHAT"S YOUR MILEAGE?

Mazda suggests changing CATS after 100,000 miles, although properly maintained, you can go further.

It is also possible for Catalytic bits to re-enter your engine via the EGR valve which could lead to Death of your engine.
I believe your car has 4 CATS, 2 pre-cats and 2 later main cats. Pre-cats for sure, inspect other cats. $$$$$$$$

My 2006 has 3 cats, i've changed at least 2 of them, but my exhaust is different than yours.

 

I haven't had any problems since the $$$$$ I put into the car in 2011. New rear cat at my own cost and all new coils (6 of them). (just over federal warranty mile limit on cat - but the problems started before I past that mile mark and the car was in dealer prior to that with the problems). I never got any response from calls or letters to mazda on it. Dealer said the cat couldn't be replaced under fed warranty because it was damaged by bad coils/engine issue and my fault basically because I didn't take care of the car. BS! I did regular oil changes and what, am I suppose to predict when a engine coil is going to fail and replace them every 20,000 miles or something?

To recap,

I started having problems when I first posted this,

The dealer found bad rear coil, so I replaced the 3 rear coils since they had it apart even though one was mis-fired.

After that was replaced, drove ok for a day or so, then similar problems again.
Took it back, they identified cat as problem and said it was safe to drive.
Drove it home, started driving next day and turtle mode, so took it to dealer.
Bad cat, now they tell me not to drive it.
I demanded loaner and had loaner car for 2-3 weeks until new cat came in.
New cat came in and replaced, fine for a week or so, then similar problems.
Now a engine coil in front was mis-firing, replaced 3 front coils.

Been fine, knock on wood since then... this is original 2003 6s, probably one of the last on road. LOL. Just crossed 100k. I hope to get rid of it soon, but after I dumped 5k or so in it I want to get that $ out of it.

This was my first japanese car, probably my last. I thought they were suppose to be more reliable but I ended up dumping $ into it for major engine problems so might as well get a BMW or something.

The new mazda styling is ick anyway IMHO, they turned the 6 into a rounded off looking non-sporty family car.

Leaning toward a 335 Xi to or Cadillac ATS (don't really like the styling on caddy though)... maybe the new small lexus when it gets face lift.

 

Way to prove me wrong erickbe!!!! Welcome back!!!

 

I have a feeling he "subscribed to this thread with e-mail notification" which means as soon as someone makes a post, he gets notified in his e-mail account!!
You can do this by clicking on "Thread Tools" at top of thread first post and choosing "Subscribe"

 

The car is basically a Ford, so you not really sure about 'Japanese car'. Mazda doesn't approach Honda or Toyota in reliability. Not even Nissan if I recall the last report correctly.


As for what you've spent on the car and all the parts that have been changed, that is not the fault of the car. There are good mechanics, and there are bad mechanics. There are mechanics who possess proper troubleshooting skills and there are mechanics who are clueless where to start without a ECU error code....

Anyway....

Had an occasional idle issue. 50% of the time the car ran fine, 50% of the time it would idle fine, but then surge pulling-away from a stop. CEL would sometimes come on, and even though I have a ScanGuage permanently in place, it NEVER pulled a code.

So I started checking the obvious-
-No splits in intake tube or PCV hose
-No loose electrical connections
-All coils were tight
-Cleaned the throttle body
-Put in a new throttle body gasket
-Tightened all the upper intake bolts
-Gave the EGR a couple of good taps in case it was carboned-up. Also pulled the EGR-to-header tube connection- was spotless.
-Put in a new PCV since I had one on-hand

STILL had problem. Behavior seemed like a vacuum leak since the car ran fine after getting-up to speed. So...

-Pulled my upper instake. Yep, one of the 6 gaskets had obviously been leaking, even though they would have been new when I installed my WeaponX coils, which was about year and a half ago. Installed new gaskets, re-torqued the intake and the car has ran great ever since.


My point is, there is a method to the madness. When it comes down to basic functionality, engines are very simple thing to understand. Too many of today's mechanics are lost if they don't have code #### to look-up in a book or on a website. Just because they started throwing part$ at it doesn't mean they were replacing parts that were truly bad.