Hi guys - I'm new to posting here, although I have found lots of great info reading these threads!

I drive a 2007 Honda Fit, manual transmission. A few weeks ago, the car starting skipping a bit while pulling a load or going uphill. No Check Engine Light. I diagnosed it as needing new spark plugs (it was time), and replaced them with Bosch Iridium plugs. Drove fine for a few days, and then it abruptly starting skipping and missing again, ramping up to what seemed like a lot of misfiring. The CEL light came on. I had the codes read at Autozone: P0300, P0301, P0303, P0304. After some research on here, I realized I should not have put Bosch plugs (or anti-seize with them) in my car, and I replaced them with NGK Iridium plugs.

Since replacing the plugs the second time, the skipping and misfiring has stopped completely - there is no detectable skipping or stuttering. However, the CEL is still on and has started blinking intermittently. The car seems to have low power pulling a load/upshifting/going up hill, and in those times the CEL blinks until the power output evens out, and then it goes back to solid. I had the codes read again today - same codes. Nothing besides the misfire codes. I am at a loss. I figured if the light was blinking there would be a more serious code or at least a detectable symptom. I'm not sure where to start. I'm a DIY type of person on a very limited budget. I would replace the coils if needed, but is it likely that 3 of them would go bad at once, and that they would cause these symptoms? Any ideas, short of going to a dealer or starting to throw money at possible solutions?

I thought at first it was bad fuel, and I'm on my second round of a fuel cleaner/injector cleaner.

To top it off, I'm supposed to drive 6 hours to my sister's tomorrow, and I am scared to really mess something up if I don't get this resolved.

Thanks for any help you can provide...

 

Try closing the gap to 0.028”.

 

Can we assume your "because its time" comment on spark plugs meant that the car has 100K miles on it or more?

If so, it's time to adjust the valve lash. Hopefully you will have the time (it takes several hours the first time).

macbuddy's suggestion of lessening the plug gap is a quick-and-dirty way of making life easy on the coils.

When our '07 started to stutter, I just replaced ALL the coils. $200 USD well spent IMO. Remember, they get weak before they fail enough to cause misfires.

 

Thanks for the ideas, you guys. The car has 235,000 miles on it. I replaced the plugs (not sure exactly when) approximately 50,000 miles ago? Pretty sure they were Bosch plugs that time too - that's what Autozone always recommends, and I didn't know better at the time.

I have read about adjusting the valve clearance and can probably make it happen this week, but not sure if I can do it before my trip. However, I assume even though it's needed, it's likely not causing my flashing CEL.

I can also replace the coils, I just wasn't sure if they were actually likely to cause the sequence of events that has happened, including the now intermittently flashing CEL, without some more obvious skipping or misfiring...

 

Intermittently flashing CEL indicates ignition misfire. find weaker cylinder by disconnecting coils one of the time, then pullout offending coil. If it looks good on the outside (no black or brown deposits on the boot) replace it with known good one. If misfire persists at the same cylinder, compression test is in order

 

Probably throwing a multiple misfire code. Check it with a BAFX Bluetooth adapter ($20) and Torque pro for andriod ($5)

I just brought an 07 Fit up from TX a month ago. First Fit, same issue. Had the foresight to send one OEM coil to destination. 10-15 miles from home, she "gunned it" getting on the freeway. Next day, threw flashing CEL. It had brand new Denso (I believe) iridiums.

I changed all four coils with a 4 pack from Amazon and all is well. Price is like $60 vs $50/ea for OEM coils.

Amazon coils here (I chose the sponsored QYL brand) -

 

No free lunch here. Aftermarket coilpacks have been known to go in as little as a month. Feel like replacing them again that soon? That's why we recommend the OEM Hitachis, as they will generally go 100K and sometimes quite a bit more.

 

Took me 40 minutes, and that's after messing around with the battery hold down a bunch. It was kinda missing, lol

I don't doubt they're not a long term solution. My car has one Hitachi sittin on the shelf, so that's a start.

So.. drive with a misfire, or spend $200, do not pass go. Gotcha chief.

 

Sauk, keep us posted how long they last. Maybe you can change our minds. In the cumulative experience on these boards, eBay coils haven't held up so well.

Hoping you have a better experience as we all want to save some money when it makes sense.

 

Even Hitachi (aftermarket) coils are weaker compared to Hitachi coils sold in dealer (did test at APEXi at very low mileage 35,000 "loaner" 2008 Fit on the dyno). The weakness (intermittent lower spark peak) shows up at ASM mode @ 25mph when using a/c at 60 degrees C under hood.
This "weakness" will probably be never detected by the average "grandma" style drivers of their meticulously maintained 180,000 mile cars (oil changed every 3 months and ATF changed every 15,000 miles)

 

I'll build up my stock of OEM's and keep ya posted. So far they seem alright, but it's cold here in MN. I'm guessing heat is a big killer of the coils because they're right over the exhaust manifold. The ones that were in it had red boots (well, almost red, pink really) so I think they were changed before. If it's general consensus that these are garbage, it would put it in line with any other car I've owned. You definitely get better ignition parts OEM.

It's kinda too bad these cars can't be tuned with HPT. Is there any other tuner for it? Not that there's much to tinker with, but it'd be nice to adjust fueling.

..valve lash, huh? Sounds like a hecka fun time!

 

I agree that heat is a killer for them. Loose plugs are the other killer. We've only had to replace one in our 190k miles and it was due to contamination from a loose spark plug. Our #3 plug loosens over time.

For tuning, we have Hondata. From my understanding, it blows the ECU wide open so you can do almost anything. I'm gathering parts for a build and it's on my list to purchase soon.

 

If you decide to do the valve lash yourself, I like Carbuff2's recommendation to use bent feeler gauges, saves your knuckles more than straight ones. After I did my first, felt like I gained an extra gear in power on my 5MT, it was that noticeable. Cost is negligible - you might need to replace the valve cover gasket, but most times you can reuse it, so it's basically valve gasket sealant and your labor.

 

The bent feelers allow you to insert the gauge into the gap without bending them. Makes for a more accurate reading.

That said, I'll ALWAYS do the 'go - no go' method.