I've recently done my cam gaskets and since putting it back together I've had a slight surge in the engine and the exhaust is puffing? Anyway checked new plugs are seated correctly and there fine.. I then tried pulling each coil pack out with the engine running and each one when pulled gives the engine a change in rpm as expected. Number 8 isn't.. no change in engine tone or rpm when it's unplugged.. could a bad coil pack cause my symptoms? .

Or a bad plug.

Check for issues with your IIDtool. If it was me I'd try the cheaper option first  ______________________________
Simon
______________________________

Range Rover Classic 3.5 efi - Gone
Range Rover Classic 3.9 efi - Gone
Range Rover Classic 4.2 LSE - Sadly gone
Land Rover 110 3.5 - Gone
Range Rover P38a 4.0 SE - Pleased it's gone
Range Rover P38a 2.5 DHSE - Just sold
Range Rover L322 4.4 v8 Petrol - Current

No faults on the iid tool, I would have thought it would have shown something. Plugs were new a month prior to doing cam cover gaskets and were fine although they did get covered in oil from the leak and I cleaned them off.. possibly the electrical contact cleaners fouled the plug? I'm hoping the puffing from the exhaust is related to the plug/ coil 👍

Swap the suspect coil to one of the other cylinders and a known good one to the suspect cylinder. If the fault moves cylinder you can narrow it down to the coil.

Swapped the coils and problem persisted, changed the spark plug and it's fixed.. new plug had only lasted a month and died.. nice cheap fix so happy with that.. thanks for input gents..

Good to hear!

Pleased it was just a bad plug. My grandad used to say start with the cheaper option first and he's been proved right quite a few times bless him.....

Regards ______________________________
Simon
______________________________

Range Rover Classic 3.5 efi - Gone
Range Rover Classic 3.9 efi - Gone
Range Rover Classic 4.2 LSE - Sadly gone
Land Rover 110 3.5 - Gone
Range Rover P38a 4.0 SE - Pleased it's gone
Range Rover P38a 2.5 DHSE - Just sold
Range Rover L322 4.4 v8 Petrol - Current