This isolates the problem down to the spark generation and distribution system which is what we've suspected for a while. Gap isn't the source of the problem. Since you've gone below spec, some other component isn't performing properly, either a coil pack, or the trigger for the coil pack (ECU? or wire). I'd regap the plugs to spec, then get one new coil pack and begin swapping it onto the plugs until I found the bad pack(s). It could also be a loose or low power feed to the packs.

I'm sticking with the bad coil pack theory. There appears to be enough power to generate a little bit of a spark and the triggering mechanism works if the problem goes away when the plug gap is small. One or more of the coil packs just isn't recharging/generating enough power to jump the gap every time.

 

For the record, I've been driving around with the original plugs (with 71K on them) gapped at .035" for the past few days, and the Fit has been running fine. My latest tank of gas showed that the mpg is normal, so I didn't experience any noticeable loss due to using a smaller gap.
UPS delivered manxman's extra set of plugs on Monday, but I didn't have a chance to install them until an hour ago. BTW, the plugs that manxman sent were made by NGK, my car shipped with Denso. Anyway, I gapped the fresh set at .045". installed them, and gave them a test run. I just got back from a ~20 mile, ride and they seem to work great! The Fit now idles without "hiccups" even with the A/C on!
I know this prolly won't work for all of the guys posting on this thread, but I just wanted to let you guys know that changing the plugs helped in my situation.
I just talked to Sam, at my Honda service department, and told him about the spark plug change. He said that in normal driving conditions, the plugs should last up to 105K. He added that his service manual states that under "severe conditions," plugs may need changing before the 100K. He commented that if one consistently runs the rpm at twice the rate of the normal driver, that it only makes sense those plugs are going to fail sooner (than the 100K). Hmm...makes sense to me!

-macbuddy-

PS-thanks for the plugs manxman!

 

Some Honda 'dealerships' love to push the problems under the counter! Happened to me... I was told that if I was contrite and went back to the dealer and got on my knees and apologized I could bring my car back.... Huh??

 

Still have the problem. Honda has opened two (2) complaints on this prob with me: deleted the first from their database.... but they still had my name there. Is this just ignoring to their own detriment??
Honda listen up: look at what happened to Toyota when they just did the bean counting thing and pushed their probs under the rug??!!
I would not own a car that had missing/stuttering/cylinder misfiring at all! Now if I bring in my Fit for a trade and the dealer finds out then the car is not worth anything??
By now Honda has lost many customers because of problems like these. There have been recalls but all I get in the mail are coupons for service at a dealership I was banned from. Go figure.