Fitted new coil pack n sparkplugs still the same

Check to make sure the vacuum line for the brake booster is not leakind and the fluid level is okay. The rush of air and loss, check the battery cables at both ends . Also look for vacuum leaks in hoses in the engine bay.

Thanks checked everthing seems ok do u think its the cat as it won't tick over

An all so to keep the car tickin over I got to keep ma fot on acc bout 2000rpm there's a knockin sound in the engine or engine bay.

Oh, that sounds like you blew your engine. You might have blown a head gasket or spund a bearing and lost some soolant, which would make the moise easier to hear, and/or oil. The knocking is not a good sign along with the issues you describe. It almost certainly sounds like a mojor engine overhaul. You could probably find a good used engine for around $1000-$1500 depending on how many accesories came with it.

Hi just had the car on the computer its givien me 4 codes 1st/ p1814 undocumented code/ 2nd/p0300 ramdon cylinder misfire/ 3rd /p0303 cylinder3 misfire / 4th/ p0304 cylinder4 misfire any ideas

You could have a bad head gasket or low compression. Get a compression test done.