3rd tank of gas now with this issue and still getting between 38-40mpg so its not affecting mileage.

coil also arrived and i swapped it onto #1. still misses. so i will be moving it to #2 and see how that goes tomorrow. if i run through all 4 cylinders and still have the miss then i will bathe the engine in chemicals as previously mentioned and hope for the best. if that doesnt fix it then im going to go trade it in for the new mazda 3 skyactiv

 

Im having the same issues, and I'm changing plus today. Let me know what you find with the coils. ALSO, wouldn't advise bathing your engine unless you plan on replacing gaskets.

 

Wouldn't a mechanic be cheaper than a new car? My previous car was a Mazda 3 and while it did drive well it wasn't exactly a fine example of a reliable car and the mileage wasn't anything to brag about.

 

A engine miss will cause lower HP and more gas usage. Your problem now sounds like motor mounts and maybe suspension.

 

i meant just using seafoam and pulling the bac to check/clean carbon deposits in the intake

i can almost fix anything i come across. this is just an excuse to trade up. the car is nearing 5 years old. check out the new skyactiv cars. 40mpg in the larger and slightly nicer mazda 3

no.. its definitely an engine miss. its just so sporadic and uncommon that it isnt having any real adverse affect on fuel economy(or power). it happens in a very narrow rpm range(well below cruising rpm) and only a slight hit every handful of accelerations from stop. its not constant or consistent. for example. my commute one way is about 17 miles. 14 of those are freeway. i felt it miss once during the entire trip to work and that is about the norm for my issue.

 

Why do you think only one coil or plug is bad? Pay attedntion, a quiz will be coming. Buy an OBD II tester and check for the conditions that are causing the misfire. Then order coils and plugs if thasts tghe culpritsd.
PS what makes you think a Maz 3 will be different but at least the tester will work for both Fit and MAZ.

 

have a tester. no codes. nothing comes up.

what are the chances that more than one coil goes bad simultaneously? i am still not even convinced that it is a coil and instead of buying a stack of coils or coil testers or any other amount of money that would otherwise be wasted, i can probably rule out coils or find the culprit at 1/4 the cost based on deductive reasoning.

there is nothing saying that the mazda 3 is better or worse or different than the fit. its just about that time to trade in anyway and being a mazda/rotary fan, i might as well make my entire fleet mazda.

dont take this as an attack. i dont need to be attacked either. my logic is sound and neither your threat of 'quiz' or use of bold will scare me off or change my methodology. if you have supporting evidence on what i should be checking then by all means, speak up. i started this thread thinking it definitely was not coils. others have convinced me that it is at least worth checking out. as well as the bac and others. but i have to rule out one thing before i move on to something else. it does me no good if i clean the bac/ change fuel filter/ buy 200$ spark plugs/ replace all coils/ seafoam it/ replace air filter/ change oil with super synthetic. sure my problem may go away but it would not pinpoint the root cause and i want to help others with a conclusive and concise answer instead of a shotgun response.

 

More than 50% of the time it is more than one item failure.
Just going out and buying parts without diagnosis will always cost you money. The proper way is to buy an OBD II tester for about $50 at many parts chains and decide what you need to buy before you buy stuff. Why not rule out all but the causes BEFORE rushing out to buy replacement parts.
Those damn coil packs are not that infalible. They may be cheap to buy for masnufacturers but expensived to car buyers. There's a very good reason cars come with OBD IIconnectors; take advantage.
And no, it wasn't meant to be an attack; just get yiour attention. I didn't take your reply either as an attack. If you took it to a dealer and he did what you did you'd cuss them for a week. The quiz comes when you try the coil pak.

 

Get a ultragauge. I dont think its the coils and a slight misfire once a day is not considered a problem. I get a miss fire like that when I pass a car. Its a lean miss fire because the ecu is not as fast as your command. It happens because the ecu is constantly changing and maps are stored in the ecu under Random Access Memory. Ethanol can cause it too because each injection is not the same. That is why I use Premium, that issue is not as bad.

 

you need to read. i purchased an OBD2 tester and i went to orileys to try their tester when mine said there was nothing on the scope. also.. i did this before i purchased a coil. keep telling me to buy a tester though.

i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester i purchased an OBD2 tester

just to get your attention

its bothersome because it has never occurred before. i did find a conversation earlier today stating that someone else had the same issue and cleaning their injectors fixed it. hopefully after i rule out coils, the seafoam in the intake and fuel tank will make short work of any carbon or debris and i can have this nonsense behind me.

 

Clean the throttle body and use Red line fuel injection cleaner. You don't need the whole bottle and can use it over many tanks. I agree its annoying but that is because the gas is not as good as in the past. I've found that out a long time ago since we had ethanol in our gas since the 70s. Premium gas around here was so much better a few years ago too, I was getting high 36-38mpg yearly average in a D17a motor driving the same route I am now. The Fit was about the same but I went through 3 winters and 2 summers. My Civic now is 36 for a 2 year average but get 42 mpg in the summers. Also its been less humid at least around here so it raises the octane requirement. I have yet to see 42 mpg this year because of it.

 

moved on to coil 2. miss is still persistent.

 

Are you replacing or checking the coils? Check the plugs again too.

 

i had a misfire once, but no CEL. rather than chasing it down like your doing, the next time it missed, instead of letting off the throttle as the regular reaction would be.... i pushed the throttle down further. the car hated it, but it caused the CEL to flash and then i finally had a code stored, pinpointing me to which cylinder was the problem. replaced the coil and problem solved.

 

i do that too. it seems like it may be more frequent after the car is fully warmed up. if i run in a higher gear.. say 5th and it puts it in the 12-1300 rpm range i can usually get it to hit. i drove all the way up a hill with it missing and stumbling and falling on its face.. still no cel.

 

odd that there is no CEL code stored.

at the time it is missing, does your CEL flash?

you definitly have a load based misifre....when the engine is working the hardest (low rpm/wrong gear/alot of throttle).
it can either be ignition problme, or mechnical. id bet ignition since it is not consistantly happenig

luckily the ignition system on the fit is very easy.
ecu provides a signal directly to the coils, which obviously sit directly on the plug, whcih then provides spark. my guess is its a coil that you havent tried yet.
the one that was bad on my car was the one furthest to the drivers side.

 

no flashing CEL. i started on passenger side. i will try the third coil today. and finally fourth tomorrow.

 

and finally we have positive results.

coil pack #3(#4 being nearest the throttle body) was the culprit. swapped out replacement with #3 when i got home and went to dinner expecting to feel hesitations and misfires. absolutely butter smooth. went for a longer drive and tried my hardest to get it to miss and nothing.

got home and swapped in original #3 coil and it started missing not even 100 yards from the house. swapped new coil in and went for another long drive trying to recreate scenario and nothing.

thanks everyone for your help.

 

Nice! Now prepare to replace the next one that goes bad...

 

Coil packs or spark plugs loose mine did that I have coils for sale new!