# P0303 cylinder 3 misfire code



## heraldvitesse (Oct 22, 2014)

New coils and spark plugs have failed to cure code P0303 problem. Vehicle also uses some coolant and overheated twice. Compression test indicate that head gasket is fine. New radiator and pressure cap have failed to cure coolant usage. Are these issues related? Vehicle sometimes runs very rough for a few seconds.


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## Old Tom (Oct 3, 2021)

Did you ever discover a solution to this problem? I am having the same issue


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## rogoman (Dec 16, 2004)

heraldvitesse said:


> New coils and spark plugs have failed to cure code P0303 problem. Vehicle also uses some coolant and overheated twice. Compression test indicate that head gasket is fine. New radiator and pressure cap have failed to cure coolant usage. Are these issues related? Vehicle sometimes runs very rough for a few seconds.


Here are some possible causes:

- #3 spark plug may be misfiring.
- Clogged or faulty fuel injector 3.
- Fuel injector 3 harness is open or shorted.
- Fuel injector 3 circuit poor electrical connection.
- Insufficient cylinder 3 compression.
- Intake system air leak.

What were the actual compression test readings? You can follow up by running a leak down test on cyl #3 to determine it's condition.


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## Old Tom (Oct 3, 2021)

rogoman said:


> Here are some possible causes:
> 
> - #3 spark plug may be misfiring.
> - Clogged or faulty fuel injector 3.
> ...


Thanks for the response. I haven’t done a compression test yet. I have 3 x-trails and 2 are running well. Oddly enough, the one I am having problems with has the lowest km.
I will keep you posted when I get more information.


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