Hi guys,

I have a 2007 Fit with ~127k km on it. In the last few months I have a taken up a DIY approach to my cars and have encountered a hurtle with my Fit. She has gotten me around for the last 7 years gracefully with not so much as a flat tire or a single CEL.

However recently in the last few weeks I have encountered my first CEL in regards to misfires. I first noticed sputtering and hesitation while idle and in the city (30 - 50 km/hour). I changed each spark plug out for a new one. I used the bosch +4 plugs.

In the city I now don't encounter a single problem. It runs beautifully, you wouldn't think anything is wrong. However the story is different under load climbing to highway speeds.

I get misfire DTC's when applying acceleration reaching around 80-100 km/hr. I get the random misfire, as well as misfires for all the specific cylinders.

I have swapped the current coil packs around without any effect, I can't track down a single cylinder that is giving me a problem, or one that is unnaffected. My next thought was coil packs? But how often do >2 die at one time?

I was hoping you guys could help me come up with some next steps.

 

If you're on your factory coil packs, have new spark plugs and are getting misfires, I'd strongly suspect the coil packs and I wouldn't find it too odd that multiple ones could go at once. You could get the OEM Hitachis for $55 (advance auto with a 30% off coupon) each, or if you want a less durable product that would diagnose the problem, you could buy four Rockauto coil pack boots for $10 each. If that's not it, I would probably either try to trouble shoot it with the service manual or just take it in to a mechanic. Also, folks on this forum generally don't advise non-oem spark plugs; only denso and NGK. Sometimes there are problems with other brands.

 

Why did you install the Bosch +4s when the OE plugs were Iridium?