Hey there,

Just wanted to share my experience with our 2007 Honda Fit and our engine stuttering problems. They started about 120k miles, we're now at 132k miles. About 9 months ago we had the stuttering issue, most of the time when the car was under load and/or trying to accelerate quickly up an on-ramp or hill. It would just hiccup, and lose power a little bit.

We took it to the mechanic, they did a "valve adjustment" which they thought would fix it. This lasted a month, and the problem still happened, so they redid the valve adjustment(owner did it) and we went on our way. $200 gone.

Next we took it back in with the same issues after a check engine light came on, they checked it, said some of the cylinders were showing codes and replaced our spark plugs. $100 gone.

Issue still persistent, we were traveling back from on a Sunday from July 4th vacation up in northern California, had been using the car all day, and with A/C on(damn it was hot). Finally check engine comes on, and car stutters badly, poor accelleration, rough idle. I opened the hood, checked all fluids, nothing out of the ordinary. We just kept it at 55-60 the next 3 hours home.

Ended up researching this forum after the mechanic wasn't in on a Monday. Signs kept pointing to coil packs being bad.

Did some research, read a bit. Found Hitachi coil packs for $47 each + S&H, these are the same as the honda parts. Ordered 4 of them, arrived 2 days later with expedited shipping.

I replaced all 4 as I wasn't interested in doing 2 now, then 2 again in a year, I just wanted a fresh start.

Car has power again, I actually spun out in 1st gear for the first time in a while. I can slam the pedal to the floor and experience smooth accelleration instead of stutter/jittery/hiccup acceleration.

Took it back to the mechanic for a victory dance, he agreed, it was probably the coil packs but said he didn't replace them at first as it could have been a few others things and the coil packs are $100+ parts each.

*** The Fix ***

1. PreCheck by user mahout
   "As stated the problem has been hashed at length.
   Here's a synopsis:
   1. regap the spark plugs to 045 to 050" instead of .055 and clean the plug electrodes; at 40k you may need new plugs anyway.
   If that doesn't clear the problem of weak coil packs or over resistant plugs, then
   2. install new plugs with reduced gap.
   3. If that doesn't work you'll likely have to replace at least 1 coil pack.
   They cost $75(& up at replacement parts stores or Majestic Honda in RI.)each so use an OBD code reader hopefully to see which one(s) are a problem. OBD testers are available at Advance Auto stores or Autozone for about $40. It won't be last time you need it."
   
2. 
   according to koolkevin1107 - "What i recommend doing is taking your car to pep boys. Tell them that you are having some kind of misfire in a couple of the cylinders. They will run a FREE check for you.. YES FREE! Just have them run the test and they will tell u "oh cylinder 1 and 2 are misfiring." After that, just take ur car home and order 2 coil packs. DO NOT let pep boys fix your car, they will replace the spark plugs only and charge u $50 and u will STILL have the same problem! It's not the spark plugs, it's the coil packs!
   
3. Order Coil Packs -
   
   Part Numbers: These are the same as the 30520-PWC-003 (old OEM part number), new OEM part number is 30520-PWC-S01 aka Hitachi IGC0053
   
   I got mine from RockAuto.com for $ 47.79 each + 15 expedited shiping
   
   Some recommended against aftermarket coil packs from brand
   
4. Follow these instructions from "Official DIY: Changing Spark Plugs" thread - https://www.fitfreak.net/forums/fit-...l15a-vtec.html
   
5. I wouldn't recommend gooping the "Dielectric Grease" like he does in the photos. This grease actually inhibits electricity flow. Instead take a Q-tip, and apply a thin layer of Dielectic Grease around the inside of the boot( the red or blue part at the bottom of the coil pack). Video for example how to do this -
   How To Properly Use Dielectric Grease On Spark Plug Wires - YouTube
6. Start the car back up and take it for a spin. I went to the mechanic who cleared my codes (PO300 - random misfire, PO301 Cylinder #1, and PO303 - Cylinder #3) ... but you may have to drive it a while to turn of your Check Engine Light(CEL) if that's still on or manually reset the ECU.
   

Other sources
1. Constant Speed Stutter - https://www.fitfreak.net/forums/fit-...d-stutter.html
2. Problems with engine stuttering/cutting out - https://www.fitfreak.net/forums/1st-...tting-out.html
3. Coil Packs for 07' fit - https://www.fitfreak.net/forums/1st-...e-model-2.html

 

Nice Summary!

Had you previously replaced the spark plugs with new Iridiums @ 100K as Honda specifies?

 

The answer is I am not sure. I am the second owner, bought it for 5k with 110k miles. I am not sure if they were replaced before, but since the mechanic did it again a few months ago I didn't replace them again when I just did the coil packs the other day.