Fault codes P0304
Discussion
Good afternoon
An engine maintenance sign sometimes comes on my dashboard for a few seconds every now and then specially when I try to accelerate.
I checked the codes and it is showing P0304 Cylinder 4 misfire.
Can anyone help how to correct it. I can do very basic DIY like changing engine oil, filters and spark plugs not sure if it's a difficult job or something that can easily be done.
Thank you in advance.
An engine maintenance sign sometimes comes on my dashboard for a few seconds every now and then specially when I try to accelerate.
I checked the codes and it is showing P0304 Cylinder 4 misfire.
Can anyone help how to correct it. I can do very basic DIY like changing engine oil, filters and spark plugs not sure if it's a difficult job or something that can easily be done.
Thank you in advance.
ferret50 said:
Be worth removing the spark plug to clean it and check for damage....crack in the insulator etc.....also check the HT lead connector or on a newer car the coil on plug connector. Could also be a failing plug coil.
Thank you for replying. I don't know what HT lead is. But from the message I understand I need to change the spark plugs?Thank you
High Tension lead.
Being an oldie, car engines used to have a distributor and a coil, these had thick leads running between them, then a thick lead to each spark plug.
The coil generated high voltage which the distributor sent to the spark plugs.
But I guess that you have a more modern system where a small coil is clipped to the top of each spark plug?
If so, your possible faults include
Damaged plug
Damaged coil
Poor connection from coil into loom...that little connector that you remove to access the spark plug
One possible test, if you can eliminate obvious component damage, would be to swap over two plug top coils and see if the fault moves.
Being an oldie, car engines used to have a distributor and a coil, these had thick leads running between them, then a thick lead to each spark plug.
The coil generated high voltage which the distributor sent to the spark plugs.
But I guess that you have a more modern system where a small coil is clipped to the top of each spark plug?
If so, your possible faults include
Damaged plug
Damaged coil
Poor connection from coil into loom...that little connector that you remove to access the spark plug
One possible test, if you can eliminate obvious component damage, would be to swap over two plug top coils and see if the fault moves.
mk08 said:
Thank you for replying. I don't know what HT lead is. But from the message I understand I need to change the spark plugs?
Thank you
You didn’t supply any details of the make or year so ferret was trying to cover all bases.Thank you
In short, if you have a misfire then changing the spark plugs is the cheapest start to tackling ignition problems, especially if they have done a fair mileage. Even if the problem turns out to be further up the chain the fresh plugs won’t be wasted.
Dogwatch said:
mk08 said:
Thank you for replying. I don't know what HT lead is. But from the message I understand I need to change the spark plugs?
Thank you
You didn’t supply any details of the make or year so ferret was trying to cover all bases.Thank you
In short, if you have a misfire then changing the spark plugs is the cheapest start to tackling ignition problems, especially if they have done a fair mileage. Even if the problem turns out to be further up the chain the fresh plugs won’t be wasted.
Yes that makes sense to start with changing the spark plugs.
Thank yu
When did it last have plugs and new leads?
If the answer is "I don't know" it's very likely that it's still on it's originals.
How long have you owned it?
Changing these is simple. A set of coil packs isn't expensive for these cars either.
I'd be inclined to change them all, cheaper than putting it into a garage for them to diagnose, and then to charge you more for the same parts. I'd be fairly confident that will solve your issues.
If the answer is "I don't know" it's very likely that it's still on it's originals.
How long have you owned it?
Changing these is simple. A set of coil packs isn't expensive for these cars either.
I'd be inclined to change them all, cheaper than putting it into a garage for them to diagnose, and then to charge you more for the same parts. I'd be fairly confident that will solve your issues.
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