E46 318i misfire/hesitation

[LeviM]

Bought a e46 318i about a month ago and now it’s developed some sort of misfire,

When started the engine sounds abit off but drives fine and quite up until you get to about 4k rpms. Anything over that and it starts hesitating until you change gear.

Replaced spark plugs and cleaned the MAF sensor and no luck, was just wondering if there’s anything prone to these engines before I put money into it.
Thanks

[helix402]

Depends if it’s an M43 or an N42.

[LeviM]

I believe it’s a M43 engine

[helix402]

Faulty coil is the most likely. Head gasket failure on these can also cause a misfire.

[g3org3y]

Any EML? Any codes on a reader (might be a worthwhile investment)?

[Elliot2000]

If you have the maf with the rectangular connector instead of the circular connector then you can run it unplugged and see how it goes, what year is it?
If it runs ok without the maf connected it could be the maf itself or possibly an air leak. If it makes no difference you can rule quite a few bits out

[g3org3y]

Elliot2000 said:

If you have the maf with the rectangular connector instead of the circular connector then you can run it unplugged and see how it goes, what year is it?
If it runs ok without the maf connected it could be the maf itself or possibly an air leak. If it makes no difference you can rule quite a few bits out

Defo worth giving a go.

When my MAF was playing up it threw up one of these:


And these on the code reader:

[LeviM]

Elliot2000 said:

If you have the maf with the rectangular connector instead of the circular connector then you can run it unplugged and see how it goes, what year is it?
If it runs ok without the maf connected it could be the maf itself or possibly an air leak. If it makes no difference you can rule quite a few bits out

It’s a 1999 model, A few people told me to do that so I’ll give it a go tomorrow and see how it gets on, thanks

[LeviM]

Elliot2000 said:

If you have the maf with the rectangular connector instead of the circular connector then you can run it unplugged and see how it goes, what year is it?
If it runs ok without the maf connected it could be the maf itself or possibly an air leak. If it makes no difference you can rule quite a few bits out

Unplugged it ran good, bought a new MAF and runs perfect now thanks for the help

[g3org3y]

LeviM said:

Unplugged it ran good, bought a new MAF and runs perfect now thanks for the help

Great news!