Hi All

The car is my son's 2000 XJ8 3.2 Sport.

Recently a slight knock/tap sound has occasionally been heard on acceleration from low speed, so under a little load pulling away.
It sounds a little to me like pre-ignition (from my experience on a car I had years ago), but I am not totally sure.

Only noticed when warm and on acceleration at low speed, and stops as soon as the gas is eased up.
Currently on E10 fuel and have not had any issues before.

Could this be a knock sensor issue? No codes or errors.

Any advice is welcome.
Thanks
James

 

Seems to have stopped after a coolant and oil top-up. Good.

 

Good. Correct oil (and coolant)levels are obviously important, but if they needed topping up, the question is, where the leaks are...
And leaks would need attention.
Other than that: I would not fill E10 into my Jags. Not even into my Fairlane, and only with a bad feeling into my van, which is quite happy with all kinds of fuels (91-98 octane or LPG) and it needs only 91 octane... It's a personal aversion against E10. I never bothered to back this up scientifically - maybe I am right, maybe not....

 

Unfortunately, here in the Colonies, we are pretty much stuck with E10 for high octane gas (maybe not in IOWA, where we had a member who ranted about us using what was available, even though we make ethanol to enrich their farmers).

Might also be sure than in filling the coolant you are using the correct antifreeze: straight water doesn't cool enough and you will get a knock.

 

I might try some Rislone Hy-per fuel additive just to see if it helps.
https://www.walmart.com/ip/Rislone-H...=searchResults