2011 Buick Lacrosse o2 sensor/misfires

[GerGa]

Hi,
Dealing with a 2011 Buick Lacrosse 3.6 with Oxygen Sensor codes.
P0134 o2 sensor circuit no activity bank 1
p0134 o2 sensor heater bank 1 sensor 1
P0300 random misfires
P0301, 303, 305 cylinder 1, 3, 5 misfires
"bank 1" is cylinder 1, 3, 5 so I hope that the bank 1 oxygen sensor being bad caused the misfires. I wonder if the reverse could be true too so maybe it's a coil.
What do you guys think?

My dad said the car was misfiring at idle a couple times this week and finally scanned for the codes yesterday.

Thanks

 

[sciphi]

Misfire would lean toward a coil instead of an oxygen sensor. Can you easily swap the coils around to see if the misfire and oxygen sensor codes follow the suspect coil?

 

[HerrStig]

It's not often BOTH the heater and the sensor signal connections go at the same time unless there's a wiring or connector problem.

 

[GerGa]

Originally Posted By: sciphi
Misfire would lean toward a coil instead of an oxygen sensor. Can you easily swap the coils around to see if the misfire and oxygen sensor codes follow the suspect coil?

Nope, they are right next to the firewall. Notice in my picture, on the left are coils 2, 4, 6 with the purple plastic on them. Below them is the o2 sensor. The other side of the engine they are right next to the firewall. No clearance to get to the coils except if I think I take the intake manifold off, which is real easy to do; it's right there on top of the engine. The o2 sensor might be accessible from underneath by reaching up but definitely not the coils. I was thinking of swapping all the rear coils for the fronts and see what happens but Ive never taken the intake manifold off one of these GM V6's before but heard it's simple and not sure if I'd need a new gasket after removing it.

 

[JustinH]

Start with a OEM set of spark plugs, and put a good o2 sensor in there.

My 2010 Toyota Rav4 was just throwing a code for cylinder 2 misfire.

Vehicle ran fine. I put 4 new denso iridium plugs in the vehicle, cleared the code and it went away.

What is the mileage on the vehicle?

 

[GerGa]

Originally Posted By: HerrStig
It's not often BOTH the heater and the sensor signal connections go at the same time unless there's a wiring or connector problem.

Oh really.
OOPS I see in my first post I wrote P0134 twice, the second one should be 135.
I think this car might be due for a visit to a competent mechanic.
Coincidentally I already ordered a Tech II gm factory scan tool this weekend, but it won't be coming until later next week.

 

[GerGa]

Originally Posted By: GerGa
Originally Posted By: sciphi
Misfire would lean toward a coil instead of an oxygen sensor. Can you easily swap the coils around to see if the misfire and oxygen sensor codes follow the suspect coil?

Nope, they are right next to the firewall. Notice in my picture, on the left are coils 2, 4, 6 with the purple plastic on them. Below them is the o2 sensor. The other side of the engine they are right next to the firewall. No clearance to get to the coils except if I think I take the intake manifold off, which is real easy to do; it's right there on top of the engine. The o2 sensor might be accessible from underneath by reaching up but definitely not the coils. I was thinking of swapping all the rear coils for the fronts and see what happens but Ive never taken the intake manifold off one of these GM V6's before but heard it's simple and not sure if I'd need a new gasket after removing it.


Forgot the picture

 

[CT8]

Try loose connectors frayed wires first.The coils be the firewall could be hotter but 3 coils going out at once?

 

[GerGa]

Originally Posted By: CT8
Try loose connectors frayed wires first.The coils be the firewall could be hotter but 3 coils going out at once?

I was just out and was able to unplug the o2 sensor. Plugged and unplugged it a couple times and cleared codes. Didn't see anything obvious with wiring.

 

[sciphi]

That 3.6 is really squeezed in there. DOHC fail for workspace.

So it's coil on plug, and the odd cylinders are on the backside of he engine. Nevermind my suggestion then.

Does the car sit a lot? Could a mouse have made a nest somewhere it shouldn't have?

 

[Ojustracing]

Its odd you have misfire on all one bank of the car. How long was it driven with the Check engine light flashing away? To me it sounds like the 02 is [censored]. But if it was misfiring a-lot it might of melted the catalytic converter down blocking the exhaust.

 

[Lubener]

How does the engine run good when first started cold? O2 sensors do not come into the equation till after a few minutes have passed after cold start up( till its heater gets going). The codes being thrown for the O2 sensor are likely a symptom of your misfiring. Don't start throwing parts at it without further diagnosis. Does each cylinder have its own coil pack? Doubtful that you have muliple coil failures. Look for something common to affected cylinders.

 

[GerGa]

Yeah maybe the o2 sensor sees the bad burn on a cylinder. The coils are notorious for going bad on these engines because they are recessed into the block. Yes one coil per cylinder. Plus with everthing packed so tight; wires, hoses, are in a very hot environment.

 

[Clevy]

I've seen misfire codes that are due to a vacuum leak.

Just spitballing

 

[Lubener]

Originally Posted By: Clevy
I've seen misfire codes that are due to a vacuum leak.

Just spitballing


Exactly. A good possibility.

 

[ls1mike]

Upon futher research the Comp G package from the factory had GAS filled struts.

 

[GerGa]

Originally Posted By: ls1mike
Upon futher research the Comp G package from the factory had GAS filled struts.

Wrong thread

 

[GerGa]

Apparently the car misfires when stopped at a stop sign or light. It's ok when driving.

 

[mk378]

Does it have dual cats? The theory earlier about the cat for that side being melted down and blocked makes some sense. Though that is usually not an issue at idle.

You're going to have to get back there-- pull coils, check plugs, compression test.

 

[Trav]

Time to get a real scan tool on this job. Fuel trim, MAF and and other sensor info in real time is a must. Without it your just dancing in the dark in a crowded room.
I would take it to the dealer, they have the equipment and usually at least a couple of guys that have been through things like this a few times and have the data base to work from.

IMHO most independents are going to stumbling all over themselves with this one. Don't keep driving this thing, the cat(s) will fail (if it already hasn't) and really run the bill up.