VE SV6 Cylinder Missfires

[Lanceee1995]

So for nearly 9 months, I've dealt with cylinders missfiring. Mainly cylinder 1 but the others have played up as well. Have changed all 6 over the last 6 months and cylinder 1 has gone again. The car shakes like crazy and when I get it back from the mechanic a week or two later it happens again. Has anyone experienced this and does anyone have a solution? Thanks in advance.

 

[h8tensv6]

Not trying to be a smart arse but you need to try a different mechanic. Could be faulty coils but you need to go to someone who can diagnose it correctly and repair it.

 

[Lanceee1995]

Yeah I will in the new year but I've gone back to this guy because the parts were under warranty so he's changed them again and again. Obviously that's not the problem there's something deeper was just hoping someone could point my in the right direction.

 

[Lanceee1995]

 

[VS_Pete]

What parts has he changed?
On the scanner P0301 is 2of2 what code was 1of2?
Any more codes?

Put that code in here and have a read may not give the answer
https://www.obd-codes.com/

 

[Lanceee1995]

He changed the coil packs again and again, initially changed the sparks so they're allgood I assume. The first code was the same as the second so I'm not too sure if that means anything?

 

[VS_Pete]

I`ll have to get my notes tomorrow (not here).
Anyway MY12 SV6 from new played up for about 4 and a half years (about every 6 months) had people look it they just reset codes.

Long story short I got a scanner and just reset codes and off we go.
Got a new catback and they couldn`t get the post O2 sensors out so got 2 new ones.

A week later it was running the worst every couldn`t reset codes so drove it to dealer they said one of the new O2 sensors was faulty and they would replace both.

I have read sometimes the front O2 sensors may upset the back if I find the story I`ll post it.
Anyway I got them to put 4 new ones in and no misfires.
I did have O2 sensor codes too not all the time. Need my notes.
PS. I`ve only got over 50000k on mine.

 

[RiCeY]

SIDI? Intake valves can carbon up enough to cause misfire.

What are the fuel trims at?

 

[VS_Pete]

My notes I didn`t write down every one.
First time no date racq came out had scanner but didn`t show codes he reset all good.

Second time about 3mths later P0301 was also in limp mode racq reset all good.

Next missing drove to dealership parked turned off car get phone call nothing wrong so must have reset itself WTF.

So after a few misfires and help just resetting I got a scanner and reset faults and away I go thinking soon or later something will fail.

4/1/2013
P0133/P0132/P0133/P153/p1153 reset all good.

8/6/2014
P0138/P0158 reset all good

9/11/2015
P0059 - HO2S Heat resistance Bank 2 Sensor 1/P0132/P0134/P0300 reset all good

11/2/2016
P1133 - HO2S Insufficient Switching Bank1 Sensor1
P1153 - HO2S Insufficient Switching Bank2 Sensor2
Reset all good
https://www.obd-codes.com/forums/viewtopic.php?t=10687

12/5/2016
P0059 - HO2 Heater resistance bank2 Sensor1
P0134 - HO2 sensor Circuit No Activity Detected Bank1 Sensor1
P0300 - Random Multiple Cylinder Misfire
Reset all good

27-10-2016
P0133/P0300 Reset all good.

3/4/2017 Hurricane Catback Exhaust Installed. They couldn`t get the post O2 sensors out so got 2 new ones.

18/05/2017
HO2S
P0054 B1/S2
P0060 B2/S2
Reset all good

21/5/2017
P0157 - HO2 Sensor Circuit Low Volts Bank2 Sensor?
P0300
Reset all good.

25/5/2017
Engine Light stayed on couldn`t reset codes.
They replaced the 2xO2 sensors warranty
Didn`t give me the codes.
As I said above about reading the pre o2 sensors can upset the back ones I put new ones in the front.
So far so good.

So in 5 and a half years these are the only electrical parts that I`ve had trouble with codes / faults.

So I just waited for something to break.

 

[RiCeY]

Front O2 sensors are used to determine fuel trims, rears simply measure the efficiency of the catalytic converters. Fronts should cycle up and down, rears should be static. They are independent of each other as they perform separate tasks.

Your scan tool should show fuel trims, what are they at when at running temp?

If you are keen pull the intake manifold off and shine a torch down the intake runners, you can see the valves and if they are caked in carbon they can cause misfire due to not sealing.