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Discussion Starter · #1 ·
I have had my Mazda 6s 3.0 for 9 months (currently at 80k), and recently it started shuddering in idle. Also, the acceleration has slight jerks in it and there is not as much power. FINALLY after about a week of this - a misfire code for 2nd cylinder came up. I replaced that ONE ignition coil and there was a good improvement of the smoothness in acceleration. It still idles kinda rough and im wondering if I should go ahead and replace ALL of the coils/sparkplugs. What else should I check? Also If i turn the cabin air on defrost (air from outside coming in) it smells a little like gas. Im not having any mpg issues but I find it strange - might have anything to do with all of this? And where does this fit in with the pre-cats? Called a couple muffler shops who "dont do that" when asked about cleaning or servicing a precat. They just want to replace them all together for 2000$. I have liked my mazda but this is starting to scare me a bit. please help. :eek:
 

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I would definitely replace all your coils along with the spark plugs if you haven't done them yet. I bought Intermotor coils by Standard Motor Products which have served me well which are cheaper than stock. Cured my hesitation issues and I have my power back again.

Muffler shops are not allowed to alter catalytic converters in any way.
 

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I would definitely replace all your coils along with the spark plugs if you haven't done them yet. I bought Intermotor coils by Standard Motor Products which have served me well which are cheaper than stock. Cured my hesitation issues and I have my power back again.

Muffler shops are not allowed to alter catalytic converters in any way.
This. I had the same issues you have, I'm sure a lot worse as I am pushing 159,000 @ present. @ idle, thing was stuttering like crazy and got to the point where I went ahead and replaced with all new coils, In fact the Standard Motor plugs mentioned. You can grab them @ rockauto.com very simple to find parts and should run around $21. Thing is amazing now with no hint of stutter, aside from the infamous occasional shift shock. As for the gas smell, not too keen on what is happening there.
 

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Discussion Starter · #4 ·
Ok, I am going to order five more coils from partsgeek.com (beck/arnley are pretty cheap).

ignition coil | Partsgeek.com

Gonna change plugs too, (if I cant find that theyve been done already in my stack of vehicle history).

Will repost on Monday when I've installed them. This forum has been a BIG help and I am very grateful.

As far as the precats... Do i just bang on them and hit em with a shop vac? lol. Im gonna read some more threads abt it. Thanks again for any more suggestions.
 

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I, too, am having the same problem. The idle is getting really rough now as well. My car is at 124,xxx miles with the V6 as well. The idle is rather sporadic, rough, and the car "lurches" if I just let my foot off the break for the car to pull itself forward. The CEL has come on, but the only code that was on there was a for a small vac leak (gas cap). I had the plugs replaced at 104,xxx mi as well as one ignition coil. Could it be that the other coils have gone bad by this point as well? I should have mentioned this prior, but the power coming from the car seems to be rather uneven as well. Like it times it seems the engine is really bogged down, but other times it will just launch like a rocket.

Could the Throttle body play a role in any of this? I think the original (supposedly defective) throttle body is still on my car.
 

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Okay, thank you. I'm taking it into the shop on Monday because its the only day I have off and the car almost died only while in idle. It does perfectly fine once I give it some gas even if I bog down the motor with a load. Could it just be that the the coil or something is misfiring at idle speeds (as bizarre as that sounds)?
 

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Just thinking off the top of my head could the Mac sensor be dirty or something or maybe the throttle body needs cleaned again just thinking off the too of my head on this one
 

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Is there a way to test the coils? I suspect I have one or more bad, but I'm on a shoestring budget and I can just do all six. No misfire codes so far..
You can load test them. In short remove them from the car, insert tester into COP, ground test lead and extend gap beyond OEM Gap to simulate load. Usually easier to just replace. AND JUST BECAUSE THERE IS NO CEL, DOESN'T MEAN THE COP(s) are not BAD!!!

Example: OEM gap is say 0.052" so you set it at (WAG) 0.075". If the COP can't jump gap but instead fires elsewhere the coil is bad. Obviously its bad if can't do the OEM gap of 0.052".

Also - its not the RPM that is the issue; its the load imposed by the engine. Firing the plug during take off requires greater spark energy than going down hill at 3000 RPM. Its why they misfire during take off. Adding additional load like AC, Lights, Seat heaters, high beams, fogs, all that makes it hesitate from take off worse, likely needs COPs.

See thread: http://forum.mazda6club.com/3-0l-v6...list-links-help-solve-issues.html#post3481346
 

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Also, don't confuse throttle lag with hesitation. It seems the 6S can have a bit of lag but it can also be corrected with a relearn. PS - Yotas and Nissans do it too as do many other makes and models.

  • Warm engine then Key off. For 3 minutes.
  • Key ON to RUN position but DO NOT start engine.
  • Slowly and evenly press throttle pedal to the floor at a consistent rate.
  • once down completely;
  • Slowly and evenly release throttle pedal from the floor at a consistent rate.
  • Remove foot from pedal
  • Turn OFF key and let it sit about 3 minutes.

Drive as normal.
 

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Discussion Starter · #13 ·
ORIGINAL POSTER IS BACK WITH ANSWERS!

Ok, so I bought the extra 5 coils (beck/arnley) and after installing them today, I got an impressive increase in acceleration - also it stopped the hesitation in 1st and 2nd gear.

THE CHECK ENGINE LIGHT TURNED OFF AFTER I CHANGED THE COIL IN CYLINDER #2 !
So even though one or more of the other coils were faulty, there were no more codes to speak of.

The back three coils were really dirty and burnt looking compared to the front three (not sure that matters). All spark plugs were clean and in good condition.

Thank you guys so much for your help! I would have tried many things to no avail if it weren't for everyone's combined experience on the matter.

Happy Motoring!
 

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That's good to hear you've got your issues resolved. As for the gas smell... check your IM gaskets. Even better, just replace them both (they can be found at your local AAP or AZ for around $20.00 give or take). Most people seem to over look these little gaskets, and yes over time they have a tendency to crap-out thereby giving you some serious vacuum leaks.
 

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I, too, am having the same problem. The idle is getting really rough now as well. My car is at 124,xxx miles with the V6 as well. The idle is rather sporadic, rough, and the car "lurches" if I just let my foot off the break for the car to pull itself forward. The CEL has come on, but the only code that was on there was a for a small vac leak (gas cap). I had the plugs replaced at 104,xxx mi as well as one ignition coil. Could it be that the other coils have gone bad by this point as well? I should have mentioned this prior, but the power coming from the car seems to be rather uneven as well. Like it times it seems the engine is really bogged down, but other times it will just launch like a rocket.

Could the Throttle body play a role in any of this? I think the original (supposedly defective) throttle body is still on my car.

Have you checked your hoses, specifically the PCV hose? I just went through everything you describe and the culprit was the hose at the rear of the intake manifold. Just a thought. I hope you get it sorted out.

 

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Have you checked your hoses, specifically the PCV hose? I just went through everything you describe and the culprit was the hose at the rear of the intake manifold. Just a thought. I hope you get it sorted out.

In fact, it was the PCV hose. The mechanic that I take it too knew about the defect in the original PCV housing/hose for the 03-04 year. So, they ordered and installed the 05+ PCV hose. Problem went away and then has re appeared a little bit. CEL came back on as well and is blowing the same "Small EVAP leak" code. I'm going to take it back to the shop when I have a day off on Monday.
 

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Buy three and put them in the back cylinders. Then you can swap around the front ones with the extras from the back. You should be able put together a good set.

Also, don't cheap out on the coils. Get good ones or you are likely to need new ones soon.

- Pete
 

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COIL PACKS FTW!!! Don't Ignore the the WARNING SIGNS!!!

ORIGINAL POSTER IS BACK WITH ANSWERS!

Ok, so I bought the extra 5 coils (beck/arnley) and after installing them today, I got an impressive increase in acceleration - also it stopped the hesitation in 1st and 2nd gear.

THE CHECK ENGINE LIGHT TURNED OFF AFTER I CHANGED THE COIL IN CYLINDER #2 !
So even though one or more of the other coils were faulty, there were no more codes to speak of.

The back three coils were really dirty and burnt looking compared to the front three (not sure that matters). All spark plugs were clean and in good condition.

Thank you guys so much for your help! I would have tried many things to no avail if it weren't for everyone's combined experience on the matter.

Happy Motoring!

If you don't mind I may use your story in my thread - It is an UNDERSTATEMENT that WAITING FOR A CEL MEANS YOU IGNORED THE WARNING SIGNS!!! Its Too LATE by then!

Phase two of the downward spiral is compression loss and FAILED CATS! The cost of ignoring that loss of power and stability is HUGE! Adding to this, extended oil changes and its the beginning of the end if not corrected!

I'm GLAD YOU TOOK THE PROPER STEPS AND FIXED IT!!! Good JOB!!
 
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