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Discussion Starter · #1 ·
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!
 

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Discussion Starter · #3 ·
>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. :)
 

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Discussion Starter · #6 ·
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.
 

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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!
 

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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.
 

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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.
 

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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!


I to experienced a weird sluggish acceleration so I investigated as my dad is an auto electrician for vehicles I took em out and the OEM plugs have almost weld marks scored into the porcelain of the plugs all 4 are the same.

I have photos to prove it, replaced them with iridium Bosch and now the car feels like a real car heaps more acceleration, tourqe and smooth idle, second set of OEM spark plugs before the Bosch one's were installed now much more confidence.
The car feels spritely and the engine no makes the other systems on point.
Fuel economy is still being assessed atm.
 

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I to experienced a weird sluggish acceleration so I investigated as my dad is an auto electrician for vehicles I took em out and the OEM plugs have almost weld marks scored into the porcelain of the plugs all 4 are the same.

I have photos to prove it, replaced them with iridium Bosch and now the car feels like a real car heaps more acceleration, tourqe and smooth idle, second set of OEM spark plugs before the Bosch one's were installed now much more confidence.
The car feels spritely and the engine no makes the other systems on point.
Fuel economy is still being assessed atm.
The marks on the porcelain are called carbon tracking. It will most likely come back if you don't replace the coil boots as well. I've also not heard very good things about Bosch plugs, I hope they work out for you but I would personally I would go with NGK plugs.
 
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