My '02 King Ranch 5.4L 4X4 has recently developed a knocking sound when accelerating, but none at all at idle. The condition seems to be getting worse. It has about 75K miles on it. Anyone have any ideas as to what could be causing this? Thanks for your help.

 

Is it knocking or pinging? If it's pinging, you need to clean the air intake components as well as cleaning the carbon from inside the cylinders. You can try some aftermarket items or have it done at the garage. I prefer to use Seafoam to do this.

 

mine did this bout a 2yrs ago thought for sure it was gone local garage said that they were bad to get carbon build up around the valves I think and causes them to stick if im not mistaken, but I used a cleaner like seafoam and no prob since

 

FP60 is a good fuel system and combustion chamber cleaner.
It's also economically feasible to use it in each tank. It helps my mileage enough to pay for itself.

 

The noise is more of a low pitched ticking rather than pinging, but I guess it could be a sticky valve or something similar. Would you apply the seafoam through the gas tank or a direct approach?