Hi all, new here. Recently got a new to me silver '09 Sport with 53k miles. Although I can't know for sure the plugs were most likely never replaced given the fact that (1) it only has 53k miles and seem like originals (2) previous owners did very little maintenance outside oil changes and a set of tires. I believe that they never replaced the air filter or even wiper blades, they both are very old looking.

Before purchasing I did look at this forum and saw the sticky'd topic here so I knew to dive into this right away. Bolt for coil packs were tight and evenly (seemed torqued up to the same spec). Plugs are lined up 1-4 in the image below, #1 was loose, I didn't try to tighten to see how far it backed out, however it was certainly backed out to some degree. The discoloring might be combustion gasses, though I've seen this sort of discoloration many times in other vehicles. Plug #2 was snugged, #3 was the tightest providing some resistance to break loose. Plug #4 was loosely snugged; seem to be seated, however essentially no resistance to begin coming out.

Thanks for making this a sticky, had I not seen I would probably not replaced the plugs until 90-100k and possibly/probably blown one out.. Looking forward to contributing where I can..

 

I'm in the middle of reassembling the top end of my Fit's engine (2008). While on a long road trip (~6k miles) the spark plug got ejected from cylinder #1, just as I was pulling over because I could tell I had a misfire. The threads were stripped to a large degree so I had the car towed home 1100 miles.

Long story short: I tried rethreading the port on cylinder #1 in-place from M14x1.25 to M16x1.25 and then putting an insert in, but then I was unable to get all of the shavings out of the cylinder (used a borescope to inspect), so I took the head off. In the process I found that plugs #2 and #3 were also loose, #2 more than #3. I rethreaded #2 as well, left #3 and #4 alone (#4 plug was still tight). Time will tell if this fix works. Now that I know this is an issue, I will add another item to my inspection checklist at every oil change: check the torque on the spark plugs. A lot less work than dealing with a stripped out port.

The good news is that once I opened the engine I can tell that the cylinders look like brand new despite 140k miles and 17 years in service.

 

I am the original owner of a 2010 Fit Sport and the plugs were never changed as far as I know by the dealer although they had done a valve adjustment and flushed the tranny and radiator fluids a time or two-

So, I wound up changing them at around 212,000 miles when I noticed the car surging/missing a few times back in July or so. Prior to that, there was an occasional chirping sound as if the drive belt were loose upon starting in wet weather. Also, shortly before I changed the plugs there was a marked decrease in fuel economy. There was no gasoline smell as others have reported.

When I took out the plugs, I noted that the plug second from the left (of the passenger side) and the coil boot had some brown staining on them. When I removed the plug, it was looser than the others but didn't just come right out. The far one on the driver's side was a little looser than the other two which seemed a normal tightness. Forgive me but I don't remember the exact number but I' pretty sure they were NGK (they did have Iridium in the description),

I did use a torque wrench and tightened to 13 ft-Lb as recommended in two YouTube tutorial videos on how to access and change the plugs, given that one of the instructors stated that Fits were known to blow plugs. Up until then, I never knew loose or blown plugs was an issue with second Gen Honda Fits-

Once I changed the plugs, there was a marked increase in responsiveness -- DUH!!! -- and the fuel economy returned.

I have not traveled that far since the change- about a few thousand miles since and thus far have had no issue-

 

Please note that there is an updated torque of 20 ft-lb on hte Fit plugs. There is a TSB somewhere on the forum that states this information.

 

Thank you! I had seen some mention of it, but there seemed to be opposing opinions regarding the change amongst various posts-

Is the current overalll consensus to go with the 20 ft-LB update?

Thanks again for the prompt and courteous reply-

 

well, I drove my Fit for about 50 miles? and it seems fine, except when I step on the gas I can hear a faint ~rattling sound. I need a second person to try to inspect this, since I need someone to step on the gas while the hood is open and I look/listen around.

When I was tightening the plugs I used 16 lb-ft of torque, and it took just about 3/4 to 1 turn to get there after finger-tight, except on cylinder #2. After what felt like 2 turns? I backed off the torque to 12 lb-ft and I got a click, but I when I set it to 13, it felt like I wanted to go a lot further.

Not sure what to do. I'll inspect it when I have someone handy to help me, but I wonder if I could be stripping the thread already at 13 lb-ft? I don't think it would be a mis-calibrated torque wrench, since it's been working great, and it's only one port that's giving me this issue...

 

Just did a full oil change and spark plug replacement along with ignition coil boot replacement on my 09 that I bought a few weeks ago. I just wanted to make sure everything was good and have that piece of mind.

From left to right. #1 and #3 I loosened by hand, #2 I had to use the ratchet with some force, and #4 I used the ratchet but it was only snug, didn't take much force to loosen it.

I replaced the NGK spark plugs with densos and gapped them at .44

 

It is the 1st post in this thread where the updated info is posted.

 

In april of 2023, I purchased NGK 94279 for my fit. Finally got them installed in August 2024, and then the car basically sat for 8 months (new job commuting out of town every week).

My buddy who's been my mechanic on the car since 2018, did the work (he also did a transmission fluid filter replacement, a transmission flush, and several other maintenance items when he did the spark plugs)>

My average MPG on long haul prior to that change was around 25MPG. Almost all of it is on 70MPH highways, and I'm usually going with the flow of traffic so > 70.

28.5 MPG for 1100 miles. Both car, and my Ultraguage confirm. Not as good as my Prius, but I'll take an almost 15% increase in MPG..

 

New owner, I've had the car about a month. 152k miles, 2010 sport. After reading this thread, I checked my plugs and this was the result. 4 new plugs installed (Denso IK22) with updated torque spec and antiseize.

 

I started getting an occasional gas smell in the car, so I decided to check my plugs and sure enough two of them were a little loose. Not super loose, but loose enough to be noticeable. The coil boots were a little discolored. Mind you, these are the plugs I installed brand-new about 55K miles ago..... I may have said it before, but 20 ft/lbs is right there in-between the range of most common 1/4-inch drive and the larger 3/8-inch drive torque wrenches. IE, at the high end of one tool and at the low end of the other and not in the comfortable most-accurate range of either (we use a similar tool where I work, and the range where it would be most helpful is in the lowest 5% or so of the scale, and it bugs me because that is not the most accurate part of the scale). Plugs are tight now and car runs great as always. Nice to have this issue nipped in the bud. But the point remains, always be on the lookout for gas smells, noise, misfiring etc or any other clues you may have one or more plugs loose. Regardless who installed them last time.

 

Every two years I make sure mine are tight. One time I went too long and I felt noticeable less horsepower. Number 3 was loose and the dielectric grease had all dried up.