This is a 5.4 2000 F150 with 203K miles.Under hard acceleration there is a tapping from the engine.Don't do much of that anymore though LOL However a light tapping noise coming from the engine is always heard when you are off the throttle and deaccelerating.Its been there for at least 50K miles but it gradually is getting worse(Naturally).Intereresting it only happens when the engine is warmed up,never when its cold and first started.My thoughts are its going to drop a value or spin a bearing .Other then that it runs fine and burns no oil.Its hard to pinpoint the location as it doesnt happen at idle and you have to be driving for it to be heard. Thoughts?

 

it is from natural wear & tare...most likely.

curious... how often do you drive this?? & how far do you drive it once behind the wheel?

 

find an old motors repair manual. there is always a section on engine noises in the trouble shooting chapter

 

It could be something simple such as an exhaust manifold gasket.

 

i was gonna say exhaust leak too,but an exhaust leak usually can be heard when its cold and when the engine warms up it goes away.when the bolts on the torque converter get loose,it makes a tapping sound that appears to come from the engine,but it is also heard at idle.(worth checking) but with over 200k on the motor,it could be like Enriched says...Goodluck

 

What oil and filter are you using..
Tapping noises could be anything from spark knock, bad fuel, misfires, valve train, timing components etc... There are a lot of moving parts. You will need to try and pin point it with a mechanics stethoscope which can be found for about $10.

 

This is just an experience that I personally had on my 2000 5.4 with 210k. Twice I had a light tapping noise and only done it while hot. Similar to exhaust leak. So I ignored it until I got the time to look it over. Before that time came I spit a spark plug.. I didn't put the two together until I had the tap again. This time it blew another plug almost immediately the next day after I noticed it. Once I fixed that one I noticed the tapping was gone.. In my case, it was a leak around the plug indicating a plug loose/fixing to spit

 

That is a good point, definitely something to watch for. However, he said it has been there for at least 50k miles. I'm confident a loose plug would not last that long.

 

Check the fan clutch.

 

Well I spit a spark plug about 20K miles ago,fixed that and I still get the tapping as always.Thinking it could be another one about to remove itself.... but dont want to pull them and ****** up whats left of thr threads.Also thought about the T convertor bolts .This noise is damn hard to find as it only seems to be there at certain RPMs and while deacelerating .Sounds like its coming from the back of the motor sometimes ...sometimes not.I have used this truck for my everyday driver for 11 years until about a week ago.Idont trust it anymore as I am on the road in the wee hours of the morning .If I could pinpoint the probelm I would consider fixing it as I have the ablities but wouldnt if it werent cost effective...Am no leaning toward the T convertor theory as I have gone thru 2 starters in the last three years Hmm........

 

Agreed with the T convertor...check that and the plugs for being loose....cant hurt.

Originally what I was getting at was a bit more sinister, sludge build up on the oil pump pick up in the oil pan...if this was short tripped....might be fine cold , but when warm more gets loose and gravitates towards the pickup screen. change the oil filter and see if this goes away for awhile (no fram please)

might also want to check the O2 sensors for being loose (doubtful) or the cats are starting to plug...or a hairline crack in the exhaust ( more probable)