ive got a misfire on my efi engine,its only just started in the last week or so,when i drive the car it starts misfiring at 4000 rpm or if i rev it in neutral it misfires at 5000 rpm,the bottom end needs a rebuild as its knocking a bit and i think the cam could be worn a bit aswell but it doesnt seem to have lost any power up until it starts misfiring then it just goes flat and wont rev past it,the car doesnt seem to be using water or oil so im a bit stumped to what it might be

 

i would start with the plugs and then work back realy

 

i took the plugs out and cleaned them up but that didnt do anything,i had a spare set of leads laying around but that didnt do anything either

 

agan i would try CHANGING them not cleaning them

 

ok i will give it a go when i get chance