1994 EXOPLORER engine RATTLES

I own a 1994 explorerThe enginet rattles on the road specially up hill like it does not have enaugh power.
I checked the psi on the fuel and it measured around 30 psi does any one one know what psi it shall have?
or heve any suggestions?......please help.

Hi, RE, Your explorer engine rattle,, All the way from here it sounds like pre ignition. (spark knock),, Recent problem? Did you switch brand of fuel? Had the timing checked lately?...... Can be a number of things, Possible carbon build up on the pistons (worst case) ........Just a few thoughts....See Ya, Clay...