my excursion makes a tapping sound intermmittently on 2000 Ford Excursion

tapping mostly happens after warm up truck has 140000 miles on it and i changed oil religiously sinceday one i am the original owner spark plugs have 30000 mls on them other than the tapping it runs strong it will tap soft then get loud and then stop for a bit than it will cycle again i have a scanner and there are no codes present

by in Glen Rock, NJ on May 10, 2011
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1 answer 3 comments
ANSWER by , May 10, 2011
lifters are common but to add, the cams do wear out as well which can get costly. take it to a shop and have them diag the tap for you to verify. Roy
COMMENT by , May 10, 2011
could it be bad injectors or timing chain or coil packs
COMMENT by , May 10, 2011
injectors dont tap. sorry it is more involved. Roy
COMMENT by , May 10, 2011
thank you mastertech6371 for attempting to help I found the problem about the tapping or knocking sound was one or more fuel invectors where not injecting enough fuel and creating a piston tap i found that my fuel filter was defective and i changed it and ran the vehicle to blow coantaminants through fuel rail and back into tank and then i took the fuel rail off and flushed rail and took injectors outb and soaked them in cleaner for 1 half hour and rinsed all of there screens out and dryed them and put them back in exactly in there original order and changed all of the spark plugs The truck runs great now I'll tell you the sound was very loud forb a while i thought it was a wrist pin or rod or something