[hraklis1]

Hi all,

I'm wondering what things i should particularly look at for the following issue:

When I'm in a low gear (1 or 2), and try to accelerate quickly, I notice a few (what feel like) "misfires" coming from the engine at the higher RPM's (~3000-4000); almost feels like a knocking, or a slipping feeling. It doesn't always happen, but I can fairly reliably reproduce it, and it's only in that 1st or 2nd gear; it happens a few times, and then resolves as it transitions to higher gears. It doesn't happen in upper gears. However, it can't be too severe at this point, as there is no check engine light.

I've run my OBDII adapter and Torque, which has confirmed that certain cylinders are misfiring (relevant data below).

After a bit of research, the first thing to seemingly do is replace the spark plugs. So I've purchased 6 spark plugs to replace them all while I'm at it. If that doesn't work, I'll take a look at the coils.

However, after that, what else should I look into? Cheers

------------

MID:$a2 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 1 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a2 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 1 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a3 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 2 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a3 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 2 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a4 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 1Count
PASS
----
MID:$a4 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 1Count
PASS
----
MID:$a5 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 1Count
PASS
----
MID:$a5 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a6 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 5 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a6 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 5 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a7 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 6 Data
Max: 65,535Count Min: 0Count
Test result value: 6Count
PASS
----
MID:$a7 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 6 Data
Max: 65,535Count Min: 0Count
Test result value: 18Count
PASS
----

[nscript]

Try compression test and check if you have even compression in all cylinders. that was the case in my car (https://x3.xbimmers.com/forums/showthread.php?t=1601011)

check if the problem is with fuel injector

[pungo]

Originally Posted by nscript

Try compression test and check if you have even compression in all cylinders. that was the case in my car (https://x3.xbimmers.com/forums/showthread.php?t=1601011)

check if the problem is with fuel injector

Don't you have a diesel engine? If so, totally different technology so I doubt the OP would have the same problem since they have a gasoline engine.


Looks like it might be #6 coil, you could swap it with another cylinder and see if it follows the coil or get a new one.

[nscript]

Originally Posted by pungo

Don't you have a diesel engine? If so, totally different technology so I doubt the OP would have the same problem since they have a gasoline engine.


Looks like it might be #6 coil, you could swap it with another cylinder and see if it follows the coil or get a new one.

i agree , but diesel or petrol misfire could happen due to fuel injectors which both engines has and loss of compression which can happen in both engines i guess.

[hraklis1]

thanks for the feedback.

Swapped out all the spark plugs this morning (surprisingly straightforward!).

A lot of them had their tips covered in a black soot - what would this be indicative of?

I also swapped the coils for cylinder #6 and #5. So will keep an eye on things. If the misfires suddenly swap to cylinder #5, I guess my next step will be to replace the coil. Would there be any point to just replacing all the coils while I'm at it, or just replace the suspected culprit?

Thanks!

[pungo]

Originally Posted by hraklis1

thanks for the feedback.

Swapped out all the spark plugs this morning (surprisingly straightforward!).

A lot of them had their tips covered in a black soot - what would this be indicative of?
Thanks!

Black soot could be due to short trips and or cold weather where the engine doesn't get to full operating temps for long enough. I'd dump a can of BG 44K in the tank to help clean up the combustion chamber.