Please help 2005 5.4 engine noise issue
Can anyone please help me with this,
OK I drive a 2005 Lincoln Navigator which is my baby, I do regular filter and oil changes, and always use premium oil and filters. I live in the UK and I cant get any dealers or customer service guys at Ford to look at my car even for a service, so I do all work between myself and a local mechanic.
About a year ago I started getting a slight miss fire at idle which didnt register on the on-board computer as a miss, and then it also started happening at cruizing speed of around 60 to 70 mph.
Then I started getting miss fires really intermediate on different cylinders that were registering, and at the sametime there engine was starting to sound a little louder, like a worn tappet/lash adjuster which wasnt too bad.
So first off I had the plugs changed to the Champion 7989, which I did due to already having issues with one motorcraft plug being snapped off in the head and I didnt want to go through that again.
The problem went away but came back a few months later, so I read some more on the forums and realised the coils can suffer from wear and give a similar issue, so I changed all 8 coils to the ACCEL superspark ones and also changed all the rubber boots.
Same again all went away for a few months but the slight miss / judder at cruising speed was still there and also the tapping noise at idle was getting really loud now.
So I had my mechanic strip the heads down and change the tappets/Lash Adjusters on both banks, on opening the heads we checked the oil flow to the cams etc and all was working fine, in fact the heads were really clean with no build ups and no scoring on the cams or followers which I know some of the F150's have suffered with.
But the noise is still present, its a loud repetative ticking at idle which doesnt fade when the revs pick up, there is still a slight judder at idle and at cruising it feels rough like its about to miss, but no miss fires are recorded. The power from stand still is still full on and accelerating at speed isnt effected its just cruising and idle.
Can somone please help me as I love my car and it look the buisness, but sounds like an old diesel when I stop at junctions and lights, and is really anoying when cruizing on the motorways.
Any suggestions are really appreciated.