V8 wont start, Please Help.

[300TDi Disco]

Firstly i notice when i had the ignition on the rev counter needle would flick from one side to the other and the got lack of power, so i changed the leads  over for some performance silicone ones and now it doesn't start. I then changed the leads back to the original ones and it still doesn't start. I have had the lead from the coil to the head of the engine to check out for a spark and guess what, No Spark. I have changed the coil as i thought the coil had gone down but still no spark. any idea's???? It has a range rover 3.5 v8 engine if it makes any difference. Hope someone can helps, Cheers

[zulublue]

Dissie Cap  / rotor arm, worth changing for a few quid.

[fezzy192]

Firstly i notice when i had the ignition on the rev counter needle would flick from one side to the other and the got lack of power, so i changed the leads  over for some performance silicone ones and now it doesn't start. I then changed the leads back to the original ones and it still doesn't start. I have had the lead from the coil to the head of the engine to check out for a spark and guess what, No Spark. I have changed the coil as i thought the coil had gone down but still no spark. any idea's???? It has a range rover 3.5 v8 engine if it makes any difference. Hope someone can helps, Cheers

hi mate  have a look if youve got a pwer feed to the coil ?
what year is it as the amplifer goes on the side of the dizzy ( i have a spare if you need lol)
hope this helps