If I drive normally and wind out the gears under normal acceleration I don't
get the knock. It's when I get the revs up over 4000 and really get on it.
This is also when the engine has had time to warm up. I used to get knock
when the engine was cold, but I had taken it to the dealer for a bad air
bypass valve at about $30,000, and the dealer said that that they re-flashed
an update to the ECM and I never notice the cold engine knock after that.
If anyone gets a chance and has similar miles and has never changed their
plugs, do me a favor. When you are on a highway and going about 60,
downshift to 3rd and floor it. Any knock???

Thank you for the replies,
John

"john.moyer" > wrote in message
news:FRDJd.22001$4I2.13754@attbi_s01...
> Has anyone notice engine knock at higher revs and strain on there 4.6L
> engine at about 62,000 miles? Does this just mean that I need to change
my
> spark plugs? (Still original plugs)
>
>