Join Date: Jan 2019
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Thanked 0 Times in 0 Posts
Groaned at 0 Times in 0 Posts
iTrader: 0 reviews
2003-2008 Mazda 6i 2.3l cold start rough idle bounce/surge FIXED
I just wanted to share an experience and solved an issue that a lot of people with my car have. I spent a lot of money in repairs, pcv hose, throttle body, 02 sensors, purge valve, foam, vac leak check and more trying to find out why my car would have a bouncy idle particularly when it was colder outside, and only from a cold start. The engine even stalled out on a couple very cold mornings. When the car warms up and cruising everything was fine.
It was because a few months earlier I put in new spark plugs from Amazon, NGK plugs that Amazon matched to my trim, much the same way auto parts stores match parts to your model/trim. Autozone even had the listing the same for that particular troublesome plug
The issue was that the plug Amazon sent to me was falsely listed as having a .052 gap, whereas the plug was actually a .059 gap according to the manufacturer and other websites. My car (2004 mazda 6i 2.3l manual trans.) owner's manual calls for a plug with a gap range of (.049) - (.053)mm. Whereas The 6 cylinder 2004 mazda 6 calls for a (.051) - (.057) gap range in that engine.
Amazon brilliantly even-exchanged me for not only the correct plugs, but a more expensive premium NGK plug with the right gap measure, even though the original purchase was 8 months prior. Sure enough this solved my idle problems. I just feel silly because I ended up paying so much to ultimately fix my own mundane error. I have owned Ford Focuses that have also been very touchy concerning spark plugs, Ford and Mazdas being so similar.
So if you have a Mazda 3 or 6 and experiencing erratic idles similar to my symptoms, check what type of plugs you have installed and make sure they are to exact manufacturer/specification as you owner's manual states. I'm sure mechanics who read this may have a big SMH to this story, but hey, a lot of us here are mechanical noobs too, and I hope this helps other poor souls out there with baffling idle problems!