I have a new (2005) stx 4.6l and noticed that when I am cruising with minimal torque on the motor I hear what sounds like spark knocking. I did a search here but they all talk about at idle and under load. I hear it when I am running along at speed. If it is the injectors how would I know?

Thanks Shannon

 

The fuel rails are loud when you’re idling but I don’t think you’re going to be able to hear them at cruising speed. Must be something besides that making the noise.

 

Have you tried a higher octane gas to see if that helps?

 

not yet, i guess that makes sense. I just don't want to run premium if I don't have to. prices approaching 2.00 and all haha I will try medium grade first. We shall see.

 

Check to see is the cam phazer problem is a problem on the 4.6. Had similar noise on my 5.4L and ser. bulletin ssm18342 takes care of it. Search this forum for the above bulletin number for others with the prob.
Duggins

 

The 4.6L don't have cam phazers just the 3-valve 5.4's