So i had cylinder 3 misfire at 81k on my 08 fit sport. I replaced all the plugs and just the pack for cylinder 3. Well that lasted 2 months and then 3 misfired again and threw a code. The error now says possible vacuum leak, engine malfunction, ignition system malfunction, or faulty/blocked fuel injector. Has anyone come across this after you have already replaced the plugs and packs? What was the issue and what would you recommend as a starting point? I dont feel like paying blindy to the dealership when they try to screw me over on simple repairs with cheap parts. Im a DIY kinda girl with a mechanic friend that helps me out when I can do some of the work myself and narrow down the diagnostic part of it. Thanks my Freak Peeps!

 

Two questions,

1- Have you had your valves adjusted?
2- Did you try swapping packs to different cylinders to confirm which was bad?

Ok, I lied 3

You only replaced one coil pack? I know in other cases replacing only one coil pack has caused the remaining ones to fail...

 

I do not think the valves have been adjusted, but its the same cylinder misfiring and not the others, so i dont think its the other packs, and we had a diagnostic run both times narrowing it to cylinder 3 causing the misfire

 

Its the same code too P0303if that helps

 

Adjust the valves and do a compression test too. A cylinder leak down test would be a another test I would run. If those tests are OK then look for a vacuum leak but I am leaning toward a burnt valve. If you had a P0300 code I would say its the valves that need adjustment but with 81K it should have been done twice already.

 

Will do, and thanks for the advice. I love this forum and have been following ya'll since before I made the purchase of my car back on '08. I 'm going to add in some fuel injector cleaner when I fill up today just for added measure since that was one of the posable problems that the code suggested. I will post my results later so future peeps with the same error have a little bit of direction.

 

Keep us updated.

 

Yes. Happened to me on my 2007 with about 85k miles. Same cylinder too, #3. See my story at link below. Unfortunately, getting the new engine did not find root cause.

https://www.fitfreak.net/forums/1st-...c-problem.html

 

Ok, so here is my update. I replaced all the coil packs again. It seems the aftermarket ones I purchased werent firing correctly. The OEM 's that I I replaced them with were working great, but now that it's cold, the misfire came back, and still in cylinder 3. I am going further down and starting with the fuel injectors and a valve adjustment today to see if that works, and going to check the plug gaps. I'm getting really sick of the expensive annual issue now. Im bout to trade in and get a Toyota if this goes down again. It took 4 dealerships to get this far. I seem to be shooting myself in the foot when I, a girl, request a diagnostic with the code read-outs. They all play dumb like the codes don't tell them anything and they need to keep my car for several days for this mysterious issue! I call......................................

 

X2 on adjusting the valves. The tight one must be @ cylinder 3. Hopefully it's just out of spec and not burned.

Also,

Sometimes it's better to stick with one shop when you have intermittent problems. That way they don't have to 'cover the same ground' initially.

OTOH, a 'different pair of eyes' sometimes resolves problems, too.

 

If you can take a picture of the tip of cylinder three plug and the others I could direct you which way to go.

When removing the plug make sure to note if it seems wet.

 

That really blows that these dealerships ur going too have shitty technicians. I can tell u right away if ur valves need to be adjusted by looking at the voltage of ur map sensor. Hopefully get it all figured out.

 

The last dealership i told them what work i wanted done vs running another diagnostic. The tech was to call me and let me know the condition. he told me the fuel injectors had buildup and the valves were tight so i had them clean the injectors and do the valve adjustment. So far she's purring and idling nicely. I made a 2 hour trip today and no lights came on, so im hoping this did the trick!

 

You should be OK now but I would use a good fuel injection cleaner like Red line SI1 Red Line Synthetic Oil - Gasoline Fuel Additives - SI-1 Complete Fuel System Cleaner There is a maintenance dose that would last 8-10 fill ups. So it would be cost effective.

 

Very old post, but, felt the need to post anyway considering I still have my 09 Fit, although, sadly, probably not very much longer. Most of you probably wont agree with the statements herein, but regardless, yeah.

My 09 Fit has 275,000 miles. I've had it since 140,000 and paid a grand for it. This is due to the fact that it's previous owner neglected the car in pretty much every way possible. Tons of little consmetic issues but nothing mechanically too wrong with it. I replaced the cv axles immediately, but other than that, it ran for atleast 20,000 miles before I decided to do anything with it, which was to give it a basic tune up. That's when I discovered the wonderful world of ignition coils. So to recap, at 160,000 I had replaced the plugs with Denso iridium plugs, and new ignition coils. I just now, at 275,000 miles replaced them again out of necessity. Long story short, it's not fixed the issue I have that is more than likely going to finally put the car in the dirt.

I did keep up on the oil changes as required, using middle of the grade components. I say that only because I dont want the impression that I neglected the car in any way to come across. The car is how I make my money. I travel all over indiana as a contractor and so the thousand dollar investment has paid off well. And I am no idiot. You keep your tools in proper care.

Now, I started getting misfires in all 4 cylinders about six months ago. The only reason I knew is because of my obsessive nature and the fact that I own an OBD2 scanner. Couldn't help myself so frequently I monitor just to monitor. Never threw codes and never felt any change. Until I did. It was like the world came crashing down all at once. Within 20 miles from the first time it chugged on me, the car is pretty much not drivable. So I checked the codes, Random Misfire, as well as misfires on all 4 cylinders. Before the car even warms up, in the range of 200 total misfires.

So, I got new ignition coils and plugs. Made no difference. Checked the fuel pressure, it's fine. Checked the fuel quality, fine as well. In the midst of this, my starter goes out. Replaced it, and what a pain that was. Oil Pressure switch was next, just fine. I have no real idea what the problem is, although I have ordered new injectors and will put them in when they arrive, but I do not have much hope. And that's ok, as it's got a ton of miles on it, and has been a great car that I will greatly miss.

As for what I meant by comments that wont be agreed with...only 1 really. The car has never, not one time to the best of my knowledge, had the valve timing done. I see so many posts about getting it done to solve misfires, and frankly, there are only 2 feasible explanations for my car. 1, is that I have the exception that proves the rule, and the other is that it's simply not as important as everyone makes it out to be. As my luck as a whole is pretty much in the negatives, I find it even more unlikely to be number 1.

Please dont think I am telling anyone to NOT get it done, as who am I to say it doesn't help? And I can see the argument already, "But SofaKing, if you had done the valve whatever, the car might have made it to 300,000 miles or more". While that could very well be true, I do not see it as very likely on the premise that in the cars history, it had not once been done. The car, up until getting parked, was getting 37 miles per gallon, which is the main reason I love the darn thing.

I can only imagine it is something more serious, and beyond anything I am qualified to do to correct the issue. I will know for sure once the injectors get here. I do hope it corrects the issue, but yeah. Im a realist.

I've been told time and again by a mechanic friend of mine that if one cylinder is misfiring, it can cause the others to do the same. I have found no evidence one way or the other to the statement, so I dont know, but, I do know that when it comes to cars beyond the 90s, his knowledge tends to get less acute, and he tends to not want to take on brand new vehicles. Having said that, MOST of the time, it's the vast majority of misfires on cylinder 1. In the range of about 150:1 for cylinder 1 opposed to the rest. But not always. There are times when they are relatively evenly spread out amongst them. I switched the cylinder 1 ignition coil to 2, and the misfire situation remained unchanged. I've checked the gap on the iridium plugs and they are all correct for the car also.

Im trying to express that I've tried everything to stave off any arguments. But I am competely open to anything I might have missed as well.

Im gonna miss the ole girl.