My wife's 2007 Fit has only 53,000 miles and has started to misfire at idle. It only happens occasionally when at stop lights. It's just a mild bump in the engine. The car drives fine otherwise both at slow speeds and at highway speeds.

Does anyone have any idea what's going on before I take it to the dealer?

Thanks in advance.

 

Coil packs are definitely a possibility in which case it'll get worse fairly rapidly.

 

It's been doing this for quite awhile. Should I have them replace all of the coil packs or only the bad one? Also, while they have the car should I replace the plugs also?

 

Coil packs are easy to replace on your own. There's a how-to on here. They are about $50 apiece from Rock Auto or twice as much at the dealer plus labor. Besides, we don't know for sure that's the issue. The plugs should be good for 100K but you can pull your own and inspect them.

 

common issues that could have this effect,
1. coil packs are a common issue but generally effect higher rpms
2. may need a valve adjustment
3. could be bad gas if it just started occuring

I would start by pulling the coil packs and checking them side by side, if one looks different than the rest, then that might be your culprit.

check engine light come on during misfire?

 

Thanks for the advice. The check engine light is not on at all. I am DIY handicapped so I guess I will have to take the car to the dealer. I have been buying gas at the same couple of stations for years without any issues. I first noticed this a few weeks ago and it has been refueled since then.

 

Use a tank of 93 and see what happens. More ethanol is getting added in 87. Could be the fuel. It's a cheap test.

 

That's typical...the CEL will not illuminate until a certain number of misfires are recorded by the ECU.

If your car is off warranty, it would be more cost-effective to look for an independent Honda specialist shop. There are a few here in North NJ. (Look for parking lots filled with Hondas.)

These "indies" are usually "tuned-in" to the cause of common problems (like Fit coil packs and valve adjustments) and the labor rates are significantly less.

 

I took the car to the dealer this morning and it didn't misfire. They put the car on an engine analyzer and could find nothing wrong with the car. After I pulled into my garage, it misfired at idle. The dealer didn't charge me to diagnose the engine.

Of course the pain always goes away when you go to the doctor.

Anyone have a clue to this mystery?

 

It's most likely the coil packs. Is the CEL illuminating?

If it was valves it would be more frequent or continuous. Coil packs just decide not to work sometimes.

 

My wife filled her tank the last couple of full ups with Top Tier gasoline and the idle miss fire has only happened once. I think another fill up with Top Tier gas and hopefully the miss at idle will become a thing of the past.

 

I had this same problem in my GD. IT was also sputtering during acceleration with about 1/2 throttle.

Misfire at idle - caused by valves. Valve adjustment fixed that right up!
Misfire on accel - caused by coilpacks - replaced coils and sparks because i was near 100k miles. Good as new!

 

I have similar issue on my 2008 LX with 116k km, both idle and accel, CEL not on at all.
once the engine completely shut off when i stop at a stop sign..... i brought it to the mechanic and he said nothing he can do unless CEL come on.....
then i brought a fuel injection cleaner, put in with gas from different gas station, no more misfire so far for 200km.....

 

The next fill up with Top Tier fuel and the idle miss is gone. My 9th generation Accord owner's manual recommends using Top Tier gasoline. I thought Top Tier was a bunch of BS, but now I'm a believer and I will only use Top a Tier gasoline in all my cars.

 

My independent mechanic pulled the codes since the check engine light is illuminated. Every cylinder has a random misfire and he thinks that the computer is bad because the misfires only occur at idle and come and go.

He is looking for a used computer with the correct numbers. Has anyone else had a bad computer?

 

Wow, a year and a half. How many miles on the '07 now? (It was 53,000 in March 2014)


Perhaps it would be useful to recap what work you have had done?




I'd be tempted to approach the issue "fresh" as if it just started happening.


Here's what I would do:


1. Adjust the valve clearances

2. Replace plugs and coils. (NGK Iridiums and Hitachi brand coils ONLY)

3. Clean throttle body (and do Idle Learn Procedure)


Honda PCM computers do not fail very often...

 

The car began missing during acceleration as well as during idle and would occasionally stall at traffic light stops. My neighborhood mechanic read the computer and all four cylinders were randomly miss firing. He replaced the computer with a used one he purchased off EBay which didn't fix the problem, but now the misfire was only on cylinder number one. He then replaced the coil pack and spark plug for that cylinder which fixed the problem. BTW he didn't charge me for the coil pack or the spark plug. This was better and less expensive than replacing all four coil packs and spark plugs. I hate just throwing parts at a problem without a diagnosis.

 

HeeHee, I won't say I Told You So.


You need to post what brand of plugs and coils your tech used, and whether a valve clearance check has been done.

See post #16.

 

Since he didn't charge me I didn't ask him. He didn't check the valve clearances because replacing the coil pack and spark plug on the number one cylinder fixed the problem. Basically the computer was indicating all four cylinders were misfiring randomly which was not correct. The new computer indicated only cylinder number one was misfiring. Replacing all four coil packs and spark plugs at 63,000 miles would have fixed the problem but would cost more money when only one cylinder was causing the issue.