Engine knocking sound

[Joseph80]

I have posted about my Throttle Body and changed and all was well until the other day.

When I was driving I could hear a knocking sound that appeared to be coming from the back of the engine by the TB.

When I rev up and release the revs I hear the knocking sound but not when I accelerate. Am going on a journey London - Cardiff and will report back if it changes.

Would appreciate any advice you could give me.


Cheers

Joseph
X308 - XJ Sovereign LWB, blue, 190,000 miles - (Prins LPG conversion)

[RichardSEL]

Is this a click-click-click or a thump-thump-thump?
Is it in sympathy with the revs -- even a idle? Or only there when you accelerate?
Does it go or change once engine is up to full temperature?
How sure are you that it's engine generated?

If only occurs when you're moving then suspect non-engine source
Use a child's stethescope to listen around engine bay -- sounds like these can transfer some distance from where they're made -- particularly if you're hearing it from the cabin

Let us know how you get on?

[xjscharlie]

Hello,
Is it a tapping sound? If so have a read of my topic on this forum "Engine tapping noise 4.0L N/A." I'm still trying to eliminate this altho i have managed to improve it somewhat. Charlie.

[Joseph80]

Sorry for the delay but IO have been away.

Thanks for your replies, much appreciated.

The knocking sound comes when I press the accelerator, as I'm releasing it the knocking sound appears but only for a few seconds. Then I press the pedal again and nothing until I release it again and the knocking appears again but only for a few seconds.

There is no knocking on idle.

Engine does sound a little rough recently, so changed oil, air fuel filter, checked the connectors around the Throttle Body.

What really concerns me is two fold, 1 - The car goes into engine safe mode at any time, driving in traffic or on a dual carriageway, make sno sense. 2-The knocking sound and rough running of the engine.

The local garage to find nothing wrong, as the engine was ok ish.. I will take the car to get the exhaust checked out as I feel she may be blowing by the manifold and this may be the cause of it, I hope.


Thanks again for your tips will keep you up to date.


Cheers.