Misfire at idle

[bronxbombr]

I have the O2 sensors and if needed anything else that may fix your problem. Before you go to autozone or anywhere for parts hit me up.

[bronxbombr]

Did you check your intake manifold for cracks, mines starting acting up the same way and didnt notice it until the manifold cracked completely

[Rodriguez]

Did you check your intake manifold for cracks, mines starting acting up the same way and didnt notice it until the manifold cracked completely

Well, it seems to be a more serious issue than the o2 sensors but ill keep it in mind. Yea the factory intake mani cracked at the neck right at the throttle body so I took one from another G (2002) and swapped it in. If this is a software issue would it be good to flash the ecu?

[duh2150]

if your plugs are fine, id check it for a lean misfire use screw driver put on the injectors one by one, put your ear on the screw driver if it clicks normal check your fuel pressure after that, your spark plugs have the most resistance to spark at idle, that is probably why its at its worse at idle, do a good check on ignition system, fuel system, and compression / vacuum do a check of each, its most likely probably not compression in your case, and because your car tosses a O2 code at you does not mean you actually have bad O2 sensor

[Rodriguez]

if your plugs are fine, id check it for a lean misfire use screw driver put on the injectors one by one, put your ear on the screw driver if it clicks normal check your fuel pressure after that, your spark plugs have the most resistance to spark at idle, that is probably why its at its worse at idle

Yea when I get some time I'm gonna pull the plugs again and take a look.

[Rodriguez]

Here are the plugs, these have less than 2000 miles on them. And heres another video.



http://youtu.be/SdEy6EQX2aw

Now it just dies :/

[duh2150]

they look fine to me, id check for vacuum leaks if it stays running if you got the pedal down, if there's a unmetered leak its probably lean misfiring it sees that your in idle but its sucking enough air to choke out and give false readings to your MAP sensor and MAF, how it runs for that first 5 seconds tells me its not ignition its pretty smooth running, try having someone start it and listen for any sucking noises,also see if you can hold the car at around 3k RPM, the intake manifold its probably cracking, sounds like a lot of hissing in the video, hard to tell if that is a leak or your intake filter, id push her outside so the sound don't echo off the walls in the garage

once you hit the gas there is less vacuum in the intake and its going to draw more air from the intake piping rather then the crack, (throttle plate is the resistance to air, more resistance/more vacuum more air draw from the crack, Idle)

[Rodriguez]

they look fine to me, id check for vacuum leaks if it stays running if you got the pedal down, if there's a unmetered leak its probably lean misfiring it sees that your in idle but its sucking enough air to choke out and give false readings to your MAP sensor and MAF, how it runs for that first 5 seconds tells me its not ignition its pretty smooth running, try having someone start it and listen for any sucking noises,also see if you can hold the car at around 3k RPM, the intake manifold its probably cracking, sounds like a lot of hissing in the video, hard to tell if that is a leak or your intake filter, id push her outside so the sound don't echo off the walls in the garage

once you hit the gas there is less vacuum in the intake and its going to draw more air from the intake piping rather then the crack, (throttle plate is the resistance to air, more resistance/more vacuum more air draw from the crack, Idle)

Hmm, If this this is cracked it will be the second manifold in less than 2 months. Could there be something causing the manifold to crack? All I have on there is a small filter. The first one cracked at the neck right my the TB. Is it possible that the MAS is damaged? I do have a spare one sitting around somewhere.

[duh2150]

Well its not unlikely that it did crack again, i myself never had mine crack try unplugging your MAF if it runs better it is probably broken then

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[Rodriguez]

Well its not unlikely that it did crack again, i myself never had mine crack try unplugging your MAF if it runs better it is probably broken then

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

Yea the MAF sensor seem to be fine, im gonna start looking at the intake at some point today, ill keep this updated. Thanks for all the help guys.

[Rodriguez]

Well its not unlikely that it did crack again, i myself never had mine crack try unplugging your MAF if it runs better it is probably broken then

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Problem solved! (For now)

So after further inspection, there was a piece that screws into the TB that must have fallen out somewhere. Im not sure what its called but it was missing and in the TB on my other G it was there so I just swapped it, here is the hole where it goes.



Again thanks for all the help. Only with Mitsubishis do you get such trivial things going wrong.