Rough idle after spark plug change - Mazda3 Forums : The #1 Mazda 3 Forum
 9Likes
Reply
 
LinkBack Thread Tools
post #1 of 12 (permalink) Old 04-30-2019, 04:15 PM Thread Starter
Moped Rider
 
Join Date: Jun 2009
Location: Cincinnati, OH
Posts: 11
Question Rough idle after spark plug change

Hi All,

First post here.

I've got a 2009 2.3 Hatch, manual transmission, 150k miles.

This car has really been rock solid. A few weeks ago i replaced the spark plugs, and since then I've noticed that my idle is somewhat rough. Only after the engine is warmed up, and only when at idle.

I'm also not getting any CEL or other indications that anything is wrong. Gas mileage seems OK. Normal driving, power seems OK. Just this weird idle. I can really feel it in my seat and the steering wheel. I have a magnetic phone mount and it makes my phone wiggle.

I'm wondering if the plugs are somehow bad. Unfortunately I disposed of the old plugs so I can't swap them back in. I replaced them with Autolite Iridium XP plugs from Advance Auto.
Link to plugs

I ran some FI cleaner through a tank, and I removed and checked all the plugs. They seem OK. Any other ideas on what to try? Did I replace my plugs with the wrong ones? Are these Autolite's just bad plugs?

Thanks!
mjrusso45 is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 05-01-2019, 11:03 AM
Le Mans: Prototype Class
 
Join Date: Jun 2012
Location: South Carolina
Posts: 1,029
>Autolite Iridium XP

There's your problem, right there.

Our cars like NGK OE Laser Iridium, and nothing else. Not even the NGK Iridium IX's.
mjrusso45 likes this.
theblooms is offline  
post #3 of 12 (permalink) Old 05-01-2019, 11:53 AM Thread Starter
Moped Rider
 
Join Date: Jun 2009
Location: Cincinnati, OH
Posts: 11
Quote:
Originally Posted by theblooms View Post
>Autolite Iridium XP

There's your problem, right there.

Our cars like NGK OE Laser Iridium, and nothing else. Not even the NGK Iridium IX's.
OK great. That's what I needed to know. I just ordered some NGK 90083 LTR5BI-13 Laser Iridiums and I'll put them in tomorrow. Those Autolites have been used for a few weeks so I guess they'll just go in the trash where they belong.
geeboss likes this.
mjrusso45 is offline  
Sponsored Links
Advertisement
 
post #4 of 12 (permalink) Old 05-02-2019, 01:15 PM
Moped Rider
 
Join Date: Apr 2019
Location: San Diego, CA
Posts: 36
I've used NGK Iridium IX for the last 50k with no perceived issues

But yes, sorry to say Autolite is Chinese junk
mjrusso45 likes this.
Birchtree is offline  
post #5 of 12 (permalink) Old 05-03-2019, 07:53 PM
Grand Am Series
 
mnussbau's Avatar
 
Join Date: Sep 2005
Location: Ellicott City, MD
Posts: 253
Garage
Report back after you replace the plugs!

2006 Mazda3 HB | s Touring | 5-speed auto | Sadly, totaled by a careless driver
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
mnussbau is offline  
post #6 of 12 (permalink) Old 05-07-2019, 10:26 AM Thread Starter
Moped Rider
 
Join Date: Jun 2009
Location: Cincinnati, OH
Posts: 11
Well, I got the NGK OE Laser Iridiums and installed them. Drove it for a couple days. Still have that rough idle after warmed up at stoplights when the cars drops to the 750 rpm level. I'm concerned it could be the PCV, which I know is a super bitch to replace. So far I'm not burning oil and still getting over 350 miles per tank.
mjrusso45 is offline  
post #7 of 12 (permalink) Old 05-08-2019, 01:11 PM
Bicycle Rider
 
Stevil's Avatar
 
Join Date: Feb 2019
Location: Aptos, California
Posts: 5
Garage
Try checking the spark plug gap before moving on to other solutions. I'm not sure of the required gap for a 2009 2.3L, so check your owner manual or a service/repair manual like Haynes or Chilton. I'd recommend using a loop wire gap gauge over a coin style gap gauge. The later have a nasty tendency to break those little iridium electrodes. Good luck!

Shinrei
2010 Mazda 3 s Grand Touring
Celestial Blue Mica
Stevil is offline  
post #8 of 12 (permalink) Old 05-08-2019, 08:19 PM
Le Mans: Prototype Class
 
madmatt2024's Avatar
 
Join Date: Sep 2013
Location: Upstate NY
Posts: 1,782
It would be good to check your fuel trims and AFR when it's doing the weird idle. It could be the purge valve, it can do some interesting things to your idle when it starts acting up. You can simply disconnect the line and plug the end going to the engine to rule it out.
geeboss likes this.
madmatt2024 is offline  
post #9 of 12 (permalink) Old 05-09-2019, 06:53 PM
Short Track Racer
 
Join Date: Jun 2010
Location: PA
Posts: 238
If checking the gap on the plugs shows they are properly spaced I had experienced that on my ‘09 3 this was a sign that it’s time to clean the throttle body. There was a TSB about it that I believe is floating around somewhere. Mine would get bad enough that the engine would stall 😊 a good TB cleaning while having the battery unhooked did the job.
mjrusso45 and geeboss like this.

'09 3i|Injen CAI|TB Mods|Nighthawk Sports|Spyder Fogs

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
tchiarella is offline  
post #10 of 12 (permalink) Old 05-09-2019, 07:20 PM
Grand Am Series
 
mnussbau's Avatar
 
Join Date: Sep 2005
Location: Ellicott City, MD
Posts: 253
Garage
MAF sensor is another thing to check...use the correct spray cleaner.
mjrusso45 and geeboss like this.

2006 Mazda3 HB | s Touring | 5-speed auto | Sadly, totaled by a careless driver
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
mnussbau is offline  
Sponsored Links
Advertisement
 
Reply

  Mazda3 Forums : The #1 Mazda 3 Forum > Technical / Model / Performance > Powertrain 2004-2009 Mazda3 > Stock Issues

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mazda3 Forums : The #1 Mazda 3 Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Rough Idle ZeusofM3 Powertrain 2004-2009 Mazda3 3 03-08-2018 08:35 PM
HELP. Spark plug issue. Tanin I Just Got my Mazda3/MazdaSpeed3! 17 06-09-2017 08:10 AM
Spark Plug (Coil-On-Plug) Boots at RockAuto.com! RockAuto RockAuto 0 01-12-2017 03:10 PM
Oil On spark plug? slavuta Powertrain for 2010-2013 3 09-17-2016 10:06 AM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
8