Resolved 1G Misfire

[dsm9010]

The car has a slight misfire at idle all the time. It's when under boost its misfire really bad but like some time but then it does it its misfire really for a few minutes an then going back it a slight misfire

 

[dsmBear]

Check your plugs and wires. Test your coil pack. Any cels? What was going on when it first happened?

 

[dsm9010]

New plug an wires I try a different coil pack. I swap the motor form my old gst to the gsx same year the motor ran fine in the gst
An no cel

 

[curt-s]

Check PTU and definitely all tabs inside of the important ignition connectors. These pieces are old; intermittent break in continuity can cause spark not to fire.
Do you have any method of reading engine parameters such as fuel trims?

 

[dsm9010]

I'll try that an no I dont

It's didnt work .... I think i might of found the problem i think one of my injector leaking but only under boost

 

[JTe]

I'm fighting a similar problem sounds like. I just ordered 4 new injectors.

 

[mikehuntisitchy]

any update on this? Very interested to see if it was the injector.

 

[GSLENK]

Injectors are pretty hardy and rarely go bad unless you are using non-gasoline fuel (e85 alcohol or oxygenated etc...) you might be in for a disappointment if you think injectors are bad. Check base timing? Wires, plugs, power transistor, coil pack? All of those are much more likely than injectors.

 

[dsm9010]

I change the injectors, wire, plugs, power transistor, coil still doing it.
I just change the pigtail on the power transistor, still doing it

Can this be the issue

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[fastmojo]

Have you looked at the gap on the plugs?

 

[o0GuitarKid0o]

Injectors can fail wasn't rare on my car had 2 fail b4 I just bought new ones check the ohms in each injectors and report back

 

[dsm9010]

I only pull one this how it look idk how that happen I didn't drop it in I use the wire to our it in
I'll check the ohms

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[thearkatek]

Hopefully you just dropped the spark plug, but if not you've got some mechanical issues

 

[Maes]

Is your throttle cable loose enough? Sounds to me like its to tight. Loosen the bolts on the im and slide the throttle cable. See if there is a change. Huge common problem that people always miss. It will cause random misfires, cels, odd idle, all kinds of weird stuff.

I'm sorry wow just noticed that picture I'm on my phone it's hard to see. Yeah how did that happen? Someone drop it?

 

[dsm9010]

I regap the spark plug an its fix the misfire at idle run great till I try to get in to boost then misfire I let off the gas I let it idle for a bit the gose back to normal

 

[jared98gst]

Did you fix one plug? Or all they all "gapped" like that? "who needs gap"

 

[dsm9010]

I regap all of them ... I just check then today they were white

 

[Maes]

Are you getting any cel?

 

[pauleyman]

Misadjusted cable will not cause a misfire.

 

[Maes]

Misadjusted cable will not cause a misfire.

Yes it will I have had expeirience with this problem 9 years ago it was a pain to find. I'm not saying that's what his problem is.

 

[pauleyman]

Tight cable is no different than slightly applying throttle. If you try and adjust sensors thinking throttle is closed, yes that can cause issues but the cable all by itself on an otherwise normal car will not cause issues.

Unless the OP has been making TPS or ISC/BISS adjustments this does not apply here and would likely not apply in any misfire situation. Further discussion is welcome in another thread.

OP you are sure you did not drop the plug then how did that happen? Whats changed lately?

 

[Calan]

Is your throttle cable loose enough? Sounds to me like its to tight. ...It will cause random misfires, cels, odd idle, all kinds of weird stuff.

Misadjusted cable will not cause a misfire.

Yes it will ...

No, it won't. The throttle cable isn't tied into the ignition circuit in any way, shape, or form.

It may cause idle issues, a sticking or rough feeling gas pedal, or malfunctioning cruise control (if equipped)... but it isn't going to cause one or more spark plugs to misfire.

 

[Maes]

No, it won't. The throttle cable isn't tied into the ignition circuit in any way, shape, or form.

It may cause idle issues, a sticking or rough feeling gas pedal, or malfunctioning cruise control (if equipped)... but it isn't going to cause one or more spark plugs to misfire.

Well since you don't believe me talk to Jon at TRE he fixed it for me when he adjusted my shifter cables. And yes it did misfire when the throttle cable was to tight caused CEL codes also for the MAF.

 

[Calan]

Um... ok.

 

[Maes]

Wow people these days. Try it on your car then tell me