Random misfire at idle ; cold engine…solved .

[DBULL]

I’ve been chasing a misfire at idle that would go away at cruising speed on my 06 LX .No check engine light,no misfire pending ,no vacuum leaks.It seemed to go away and randomly return.A throttle body cleaning and an OEM maf sensor seemed to help only to have the misfire return.Although it hasn’t been too long since I installed new plugs and fuel filter , I ordered new plugs along with new coils and a new fuel filter. I elected to try the filter first just to narrow down the problem.When I drained my old filter to see if there was any water the fuel was fairly clean but when I blew into it it had a lot of restriction.At any rate,my LX has been misfire free for about two weeks.One thing that I have noticed is that the last three filters have had a made in China sticker,although they were supposedly name brand(s) NAPA,WIX and Mahle.Another thing is that the 06&07 models used a variable speed fuel pump that would increase pressure at cruising speeds. I hope that this helps anyone with a similar problem.

 

[excessive]

Could be :

Fuel pump going bad
injector bad/ going bad
bad coilpack
burnt valve

 

[DBULL]

I’m pretty sure that my misfire/stumble was simply the result of a clogged fuel filter…It’s running great now…

 

[cl100]

If your misfire returns check the coils. I've had it occur twice that the coil would crack down the side and only cause a misfire at idle. It never would turn on the CEL. I had to do a visual inspection before I found the problem coil.

 

[DBULL]

If your misfire returns check the coils. I've had it occur twice that the coil would crack down the side and only cause a misfire at idle. It never would turn on the CEL. I had to do a visual inspection before I found the problem coil.

I have a set of coils and iridium plugs on standby.That will be my next project.My plugs are at about 40k,but I’m wanting to make sure none are backing out. I had one coil drop out earlier this year so that’s probably a sign that they’re due.

 

[OEMGUY0720]

Curious to see the condition of the ignition plugs and spark plugs. Pls post pictures of them when you can.

 

[100s4bd]

I’ve been chasing a misfire at idle that would go away at cruising speed on my 06 LX .No check engine light,no misfire pending ,no vacuum leaks.It seemed to go away and randomly return.A throttle body cleaning and an OEM maf sensor seemed to help only to have the misfire return.Although it hasn’t been too long since I installed new plugs and fuel filter , I ordered new plugs along with new coils and a new fuel filter. I elected to try the filter first just to narrow down the problem.When I drained my old filter to see if there was any water the fuel was fairly clean but when I blew into it it had a lot of restriction.At any rate,my LX has been misfire free for about two weeks.One thing that I have noticed is that the last three filters have had a made in China sticker,although they were supposedly name brand(s) NAPA,WIX and Mahle.Another thing is that the 06&07 models used a variable speed fuel pump that would increase pressure at cruising speeds. I hope that this helps anyone with a similar problem.

I have been chasing a rough starting idle and a stumble that goes away once the engine is warmed up. I shot the parts cannon at it. New Mass Airflow Sensor, new upstream O2 sensors, new fuel pump and filter, PCV Valve, grommet, and hose, fuel filter. I finally bought a smoke machine from Amazon for $50 and this morning I discovered the throttle body gasket is leaking, which explains why it goes away once the engine gets hot. I highly recommend a smoke machine test to search for a vacuum leak. There are a LOT of vacuum lines. Good Luck!