P38A Emissions

1995 4.6 V8 210k
Only just failing emissions and suspect one cylinder is not firing properly. Not a full blown misfire, more like a not full fire on one cylinder.
Changed plugs leads and coil pack.
Suspect a burnt ish valve
Going to compression test then take heads off
Anything that I should do at same time?

Did the old plugs look a nice colour? What exactly is it failing in?

They were a bit blackk but that was probably from being started just to move it
I had noticed the partial misfire a while ago when pulling hard.
Fails on hydrocarbons after the hi speed bit

Have you tried an Italian tune up?

Rubberknees said:

Have you tried an Italian tune up?

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A good call with some injector cleaner?

Not entirely sure it does very much

So many reasons HC can be high.
Can you see the injector times or fuel trims?

Mark Piercy said:

A good call with some injector cleaner?

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Not convinced they do very much

Could also be a coating of soot on the cat surface

Mark Piercy said:

Could also be a coating of soot on the cat surface

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The cat doesn't remove HC? That's essentially unburnt petrol
Could be an air leak.. somewhere, dying o2 sensor, dying maf, dying cam.. dodgy plug..
Need to narrow down is it just one or 2 cylinders, a bank, or all cylinders running rich

Make sure the exhaust isnt leaking ,drawing air upsets the lambda sensors and it dont take much..

I don't think you need to pull the heads to be honest

Thanks for all your replies
Before MOT I intended an Italian Tune up but had a heart attack so that didnt happen
Lambda sensor was changed just before MOT cos Nanocom said it was

Sorry to hear that, hope you're on the mend!

Yes thank you
Got another two stents

oakey said:

but had a heart attack so that didnt happen

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I wouldn't recommend an Italian tune up for your condition. Hope you're recovering well.

oakey said:

Yes thank you
Got another two stents

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What is it about owning Land Rovers that seem to make a lot of us ill?

Montyjohn said:

I wouldn't recommend an Italian tune up for your condition. Hope you're recovering well.

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Think he meant for the car, not the heart

oakey said:

Yes thank you
Got another two stents

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A beginner conpared to @Dopey.

I'd do the conpression test and then reasses. New plugs and leads might help if compression all good.

My compression tester which I hadnt used for years, didnt fit. Need to make an adapter of some kind. Will see what results are this week I hope if allowed out to play
Thank you for all your good wishes