"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)

Is the knock sound like a timing/low octane fuel knock? Do those cars still
have distributors? If so check your timing. If not, try running a tank of 93
or 94 octane thorugh it (or whatever your highest octane pump gas is) and
see if it makes a difference. These days auto makers often run timing right
on the edge of knocking through the use of knock sensors. Could be something
it out of whack, maybe the knock sensor isn't working right or something has
changed messing up the computer's caculations. Running higher octane fuel
could compensate enough to stop the knocking. Of course if the knock isn't a
timing or fuel octane type of knock you can disregard all this.