Hi guys anyone help with this problem
My car has not been started for over a week when I started it today it sounded as if a tappet was abit noisy have tried letting it idle for a while but it hasnt cleared so I plugged in and read the error codes
they are
misfire detected on cylinders 2-3-4-7-8
misfire detected ramdom or unknown cylinder
misfire detected catalyst damaged cylinder 3-7

I have read codes and cleared them and read them again still the same
my car is Jan 1997 840c I have owned it 2 years and have never had the cats off someone said take them off and bang the s*** out off them they met be clogged up should I do this and how do I fix a noisy tappet is it safe to drive with the tappet like this

I had a similar problem on my 97 840 throwing all kinfs of missfire codes, especially under hard acceleration. My cats were clogged and I had them replaced. The car runs so much better now. You will need to replace the cats. I don't think a simple bang would work and it might make it worse since the cats are essentially a platninum coated ceramic block. You can use aftermarket cats too. They are much cheaper than stock.

If my car sits for a bit it will have a bit of a tick in the valve train. After a little driving, it goes away. Just make sure you have enough oil in the engine

-Douglas

thanks sardonumsei you were right I took the car for a drive and it is now quiet again I was worried wasnt sure what to do my oil level was fine
I am going to do some work on the car at the end of May met take the cats off and set pipe in to see whats it drives like what do you think

Same thing on my 97 840Ci last year.
At around 4000 rpm sudden power loss and misfire errors.
Long story short, both Catalyst were broken.
IMHO it doesn't make much sense to use original Cats as they are expensive and the ceramic will breake one day again.

The Cats can be opened, and then metal cats can be welded in.
That's what I've done and it works great (and costs far less).

Cheers,
Steve