16v misfire

[midz16v]

Went out earlier to start my car and found the battery dead.
Its been running out of charge alot lately,so i bumped it down the road and it fired up nae bother,was almost out of fuel so went to the garage.
Left it running while i fueled up(tesco super un)and headed for home,when i got out the town and opened it up i get a very noticable mis at around 4k.
The car wasnt mising on the way to the garage but is now.
Any ideas as to what could be wrong?

[sprout99]

bad earth?

[midz16v]

Am just in and have an update,turns out it was the hall sender plug it keeps slipping off so its now tie wrapped on
Was out in it this morning and the rev counter was jumping up and down all over the place and the car was struggling for power,when i stopped i wiggled the plug about and all went fine.
Hope thats it sorted anyway
Cheers for the reply
martin