[5soko]

Well I had some misfire issues on cold start, and finally a injector gave up (stuck open) on a cold start, dealer changed all 3 injectors on bank2 (4,5,6)

Cold start misfires were gone and car was running great. Also changed the plugs right before they changed my injectors.

Now here is my issue... bank1 (1,2,3) still has the old injectors.

When I fully warm the car after a drive, then park the car.. After I let the car sit for say 2-3 hours, oil temp back down to lowest temp on the gauge (160). I go to start her, and it rumbles and shakes until the rpms settle to a easy nice idle.. But during that rumble, I get a cylinder 3 misfire.

Does this sound like somewhat of a injector issue again?
Cold starts are great. WOT car is running and logging perfect. PLugs are new. Injectors 4,5,6 are new. Misfire only on cylinder 3 no other codes.

Only happens when the car is warm, and I let it sit for a few hours and go back to start it.

27k miles, FBO, 93 octane. No meth or E85 at the moment.

[joec500]

Yup... Typical symptom of a leaking injector. Fuel leaks as the car sits. When you start the car, that cylinder with the leaking injector has more fuel than it should thus creating a temporary rich (too much fuel) condition. As the excess fuel burns off it settles back into normal operation. Time to change the other 3 injectors and the plugs as they could be fouled. If you keep running the car in excessive rich situation, you will burnout your catalytic converter in Bank 1. Ask me how I know. :/

[5soko]

Originally Posted by joec500

Yup... Typical symptom of a leaking injector. Fuel leaks as the car sits. When you start the car, that cylinder with the leaking injector has more fuel than it should thus creating a temporary rich (too much fuel) condition. As the excess fuel burns off it settles back into normal operation. Time to change the other 3 injectors and the plugs as they could be fouled. If you keep running the car in excessive rich situation, you will burnout your catalytic converter in Bank 1. Ask me how I know. :/

haha, im 100% catless so its cool. Yea that's exactly what I was thinking, was just a bit confused there wasn't any misfires on cold start up, on this warm/cold situation.

Gonna have to dealer it again, but try to set a exact time gap after the car is warm for them to recreate this misfire. I can make it happen everytime.
But the cylinder 3 misfire should get them to dig.

[5soko]

Brought it to the dealer this am, and got it back this afternoon. Like I described, I was getting a cyl 3 misfire, after the car would sit for a few hrs... never during driving or WOT, only during starting, after it was warm, and sitting for a few hrs.. So the said that they found cyl 3 spark plug to be fouled (I just changed the plugs not too long ago, 4K miles) and the coil had spark marks or something on it, they replaced the coil aswell.
IF it was the plug being fouled or coil, wouldn't this misfire be persistent? Im gonna try to make this cyl 3 misfire come back again tomorrow, if I could. Only makes sense that's its a leaky injector. Well see if im able to make the misfire come back. Would be weird if it doesn't.

[enrita]

Originally Posted by 5soko

Brought it to the dealer this am, and got it back this afternoon. Like I described, I was getting a cyl 3 misfire, after the car would sit for a few hrs... never during driving or WOT, only during starting, after it was warm, and sitting for a few hrs.. So the said that they found cyl 3 spark plug to be fouled (I just changed the plugs not too long ago, 4K miles) and the coil had spark marks or something on it, they replaced the coil aswell.
IF it was the plug being fouled or coil, wouldn't this misfire be persistent? Im gonna try to make this cyl 3 misfire come back again tomorrow, if I could. Only makes sense that's its a leaky injector. Well see if im able to make the misfire come back. Would be weird if it doesn't.

fouled by what? was it oily or sooty.

[5soko]

Originally Posted by enrita

fouled by what? was it oily or sooty.

no idea, the tech sheet doesn't say. ' removed plug and coil. inspected. found plug fouled. R&R spark plug' - that's what the tech sheet says.

If the plug was fouled, wouldn't it show on cold start, daily driving, or WOT? it would be a consistent misfire.

Plugs are 4K miles old..
Car runs great and logs great with no codes with this 'fouled plug'

Only time I was getting a misfire for cyl3 was after it was fully warm, and I let it sit for 3 hrs and went to start it again.. ONLY scenario I got a misfire cyl3 on startup.

Coldstarts were good, warm starts good, WOT good..

Tech sheet, also said they replaced coil because it had "spark over marks"

Gonna go out now to see if I can get the misfire to come back again using that specific scenario..

[Mike@N54Tuning.com]

Originally Posted by 5soko

no idea, the tech sheet doesn't say. ' removed plug and coil. inspected. found plug fouled. R&R spark plug' - that's what the tech sheet says.

If the plug was fouled, wouldn't it show on cold start, daily driving, or WOT? it would be a consistent misfire.

Plugs are 4K miles old..
Car runs great and logs great with no codes with this 'fouled plug'

Only time I was getting a misfire for cyl3 was after it was fully warm, and I let it sit for 3 hrs and went to start it again.. ONLY scenario I got a misfire cyl3 on startup.

Coldstarts were good, warm starts good, WOT good..

Tech sheet, also said they replaced coil because it had "spark over marks"

Gonna go out now to see if I can get the misfire to come back again using that specific scenario..

If that didn't fix it at least next time you bring it in they will have to change the injector.

Mike