Bmw X5 2005 misfire

Maintenance/Repairs
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1

Hi guys
I have a BMW X5 2005 3.0 6 cylinders and 2 days ago car started shaking and check engine light came on.
Check for the codes and it says P0303 code which is a misfire on piston 3.
Changed all spark plugs but it’s still the same. Car lost a lot of power and it’s shaking a lot when it stops. If anyone know what is happening please help. Is the only car i got and don’t want to lose my job

2

Try swapping the ignition coil from cylinder 3 to another cylinder.

If the miss moves with the coil, it’s the coil.

Tester

3 Likes
3

I did it i switched with 4 & now i got misfire on both 3 and 4

4

Gee?

I wonder if you need new coils?

Tester

5

Probably it’s one coil but even when i moved that coil it still says that i have a misfire on 3

6

was the code cleaned after you moved 3 into 4 ?

7

If you want to try something yourself, replace the original coil 3. If the misfire code continues on 4 and the engine continues to run poorly, replace that coil too. In order to get the necessary number of loops to produce 40 thousand volts +, coils are made with very thin wire that can break as the coil dimensions change with temperature.

1 Like
8

Coils are a common failure on BMWs of this vintage. If you go to the BMW dealer, they are selling a different brand for this car now, not the oem Bosch. They say it is better. It had better be be better for $110 each!. If your dealer stocks the original Bosch coils, they charge $55 each for them.

You can get original Bosch coils on line at a vendor like ECS for less than $25 each. I bought one expensive one from the dealer so I could get to work, and two Bosch coils on line.

I have two 2004 BMWs. The one with 225k miles has had three coils replaced (other three will fail sometime, I expect) The other with 155k miles still has all its original coils.

1 Like
9

I had only misfire on 3 after changin all spark plugs nothing changed, so moved coil 3 to 4 ond coil 4 to 3 to see if the code will move from 3 to 4 bu what happened is that now i got misfire on both of them

10

Ok guys thanks very much. I’ll replace the coils and i will let u know

11

When you replaced those spark plugs, was there any oil on the spark plug wells? A leaking valve cover gasket will slowly fill the spark plug well with oil. A little oil can short out a plug, and is more likely to do it when the engine is cold,

1 Like
12

I think one os spark plugs had some oil. I didn’t pay a lot attention to it, what does it means