Hey All, I rarely have posted much on here since I took delivery of my 09 Fit back in October 2008, but I wanted to share something that was concerning me about my trusty ole Fit. With 214,000 miles, I started to experience what I thought was an automatic transmission shudder while driving. I was in denial a bit because I change the transmission oil with Honda oem synthetic very 30,000 miles and even have replaced the “fun” to get to external factory transmission oil filter at 150,000 miles….that was a story in of itself as a dealership kept telling me that my Fit did not have a transmission oil filter when I tried to purchase it from them. Oh well I did take care of it when I found the OEM part on line and ordered it. Back to the present issue, it seemed to happen after 20-30 minutes of driving for the past month or so…the car would just shudder quick while accelerating. Since I have always done all the service and repairs on my Fit except for the recall fixes for air bags and front transaxle shafts replaced, I started to research “transmission shudder”. After a few days of on line research, I started to think/hope my issue was something else. It was another fit owner describing a similar symptom plus noticing the smell of gas!! occasionally.

This being a possible sign of a misfire due to spark plugs or more likely coils needing to be changed out. I did replace plugs at around 130,000 miles but my Fit still has the factory coil packs. Long story short, I ordered the following shown in the photo and dug in this past Saturday am replacing. I have become pretty good at removing the wipers and under hood cowl section over the years for various reasons. I just wanted to share that this job is not bad at all and omg what a difference it has made for my Fit. Not only is the misfire gone, but my car has noticeably better acceleration and seems to idle smoother with app 100 higher rpm.

I love this car and glad to have resolved the issue with some new parts and my elbow grease. I used NGK iridium plugs before with good results and went with them again along with denso coil packs based on online suggestions. The factory ones I removed were Hitachi brand btw.

 

Nice writeup and pics, thanks.

I have 157,000 miles on my 2010 Tidewater Blue Metallic Fit Sport. Haven't changed the plugs yet, concerned that I'll break something taking off the cowl and cover stuff. Do all my other maintenance myself other than the axle and airbag recall. I'll have to try the plug change and see how it goes.

 

Thanks for the post you made here and the description of what you did to fix the stutter/ drivability issue of your car. You mentioned you replaced plugs at 130k miles and again recently. I'd appreciate knowing what torque you used both times on the plugs, and if there was any issue of loosening of the plugs in between the plug replacements?

As many members on this forum know, there is a loosening phenomenon on Fit spark plugs- especially plugs that are under torqued. The latest info I've been able to deduce on this forum is that it's recommended to increase the original factory spark plug torque from 13 ft lbs to 20 ft lbs to help avoid the loosening. Any input would be appreciated.

 

I'm glad the problem was resolved so easily. Everyone change your plugs! 20ft./lbs!

 

@Fit09Pete Good work.

 

Sorry, it's not that simple. Reading through the voluminous number of posts here on the forum about the loosening spark plug problem, the recommendation by some people posting of increasing the torque of the plugs to 20 ft lbs, is a suggestion of something they used to help the problem, but is not an end all/ cure all for the problem. More feedback posts by people increasing the torque and then posting results is needed first.

My earlier post asking the OP to post his torque specs after replacing his plugs twice is my attempt to find out what worked for him, and add to the data of what works for plug installation.

 

Regarding what I did in terms of spark plug torque, I did not use a torque wrench either time. I do not use any oil or anti seize on my fit spark plugs. I torque carefully ie slow once I feel the plug begin to start squeezing down on the plug washer. After that point, I keep going until I feel it fully compress the washer and sense a point of stopping. I’m sure this is not ideal but it has worked for me being careful not to over torque. I then check on them every 30,000 miles or so. I have not had them loosen up after the first change. Anyway, that is what I did 😀😀

 

When I swapped my plugs and coils at 89k I torqued to 20 ft pounds and used just a drop of anti-seize. Sitting at 115k now, still running like a champ. I bought Hitachi coils but swapped plugs for some colder Denso plugs. It really wakes up at higher RPM now on 89 octane. I've had the pleasure of driving three other Fits at various mileages (57k 09 manual, 162k 09 auto, 80k '10 manual), nothing comes close to how hard mine pulls now.

 

☝️ That makes me super happy to hear. I haven't driven any other Fits. It's nice to hear some validation!

Also, OP, your method is perfectly fine. I know spark plug/parts makers say to listen to manufacturers instructions above theirs. I'm certain there's engines where that's totally true, like they made an unconventional design or materials choice and have a good reason for their advisements. But spark plug manufacturers, at least the premium ones that are actually advancing the industry with engineering, know their product just as well as car manufactures know theirs, and sometimes better I'd bet, because there's less variables.

They say using torque angle is valid to the extent that it's a printed option on the box of many individual plugs as an acceptable alternative to measured resistance. I'm starting to think that so long as torque angle isn't used as means to save effort (with the exception of torque to yield fasteners where it's required) it shouldn't be demonized.
Thought the old school guys were just cheap and lazy, but maybe it was just the ones that gave me advice that I bungled way back when.

 

I just finished changing out on the spark plugs on my 2011 Honda Fit with 125K miles. I was thinking about changing the coil packs, but decided to leave them alone. It was a little tricky getting everything off at first, but re-installation went a lot faster and smoother. We will see how this effects mileage, but so far the car seems to start up a little smoother (might be placebo). I was originally going to inspect and adjust the timing, but decided against to as there isn't excessive or loud ticking when the car is idling from some of the YouTube videos I'm seen.

 

Nice job! I bet you get another 75,000 before the coils need replacing anyway plus now that you have learned the steps to get at the plugs, the coils will be a cake walk. Good luck!