Hi everyone.
First off. I have been searching these forums a lot and have acted on the advice here so far. I want to thank all those that contribute so completely of their experiences. This place is so useful.

My Fit is a GD1 2002 with a L13A.
Approximately 145,000km

I have the "dreaded misfire" issue. My car is a good long range commuter, most trips are about 40km each way to work. (I live semi-rural)
Symptoms: On hills, inclines, lower engines speed when accelerating below 3000rpm, I get the occasional cough/jerk/hesitation. This leads me to believe at first it was something to do with the primary spark plugs and coils.
No engine light present. I did get one when I tried replacing my coils with second hand ones, but this was merely old tired second hand coils. Went back to intermittent when original coils returned. Thats why I got a set of new ones.

What I have done.

• I changed spark plugs (primary) at first with Bosch ones and then recently with new NGKs (same type as I originally took out) I suspected going for cheaper ones might have done this. No change.
• I purchased brand new primary/front coils from Honda. Matched part numbers. The whole bit (This I was trying to avoid) No change in behaviour. Disappointing and expensive.
• Lastnight I took the EGR valve off and cleaned with carb cleaner. Scrubbed with toothbrush and put back on the car. I made sure to move the small circular valve up and down which I read needs to happen.This is the only thing that had a real noticable effect, it wasn't that dirty imo, but this morning my fuel economy computer reports 5 litre per 100km. This is the first time in 8000km that this has happened, but unfortunately still 8-10 hesitations today. So positive change, but still hesitations. I was almost celebrating this morning, then it did a jerk or two. Frustrating.
• CVT fluid change + additive with Honda about a month ago. Unrelated, but this has been done.

Unfortunately this is beginning to get expensive and beyond what I have read and know. My cheap little run about has this tick, this little hop occassionally... even those I pick up on the way to work now joke about it.
What the heck is doing this?

I have tried to diagnose this logically based on what I have read, and I do have to drive for a good 20-30km before the hesitation appears, but thats not good when its most days that I do this.
The thing about this is that I feel taking it to Honda, they won't see this issue because of how warm the car has to be to do it.

When the issue happens if I plant my foot and grt above 3000rpm it smooths out and is fine. I believe (however I could be wrong) that the back set of coils and plugs are functioning in this case.

Does anybody have any further ideas?

 

I have a 07 Fit Sport and had the same dilemma. Misfire with no code being stored.