I am new member here so may not do everything right.

2004 F150 5.4 engine; 110,000 miles. Just bought truck. Problem: random tinny noise in right side of engine at idle. Starts and runs perfectly at idle and lower power, but put accelerator on floor at highway speeds and it starts missing, bogging down, finally picks up speed; top speed is 85.

No check engine light, good oil pressure, engine temp. Don't know how old plugs and coil packs are.

Took to my Ford dealer and another shop; total spent about $850.00, but no help at all, they don't have an answer except to tear it down.

I don't know what to do now, I really like the truck, but don't know where to go or what to do at this point.

I could really use some suggestions. Thanks, John

 

The noise is probably the tensioner on the front of the head its ran off oil pressure....they click really bad on some 5.4's

 

I assume the fuel filter has been changed?

 

One other thing. What did they do for $850 if they didn't change the plugs?

 

Plugged converter?

 

did they take off the valve covers or not?
Yeah it might be a cam phaser as alluded to above, or it could be something in the valvetrain(word?) or, it could be rod knock if you got really excellent luck.
The mechanic shoulda been able to give you a best guess as to the noise.

 

Thanks for all your posts. I've been out of town and couldn't answer.

The fuel filter was changed by my independent mechanic in whom I have convidence, however I later verified by taking to Ford dealer.

The first mechanic replaced #3 and #4 plugs but problem wasn't helped that I could tell. I questioned them about the remaining plugs, was told they were okay, which I now doubt since they are difficult to replace. I questioned how other plugs were tested; said under load using transmission. However they went on to reccommend all remaining plugs to be replaced due to mileage.

Checked fuel pressure, found TSB re this complaint and took to Ford dealer and had reprogrammed; no improvement. Tried air flow sensor, checked vacuum, accelerator position sensor.

I asked them to pull right valve cover; said they found cam to be rounded on @3 and said running problem couldn't be fixed until cam and #3 rocker were replaced. Ford camshaft was on back order for 60 days approximately. I verified back order with Ford Dealership and took truck home.

Waited a few days and took to Ford dealers top mechanic. He drove truck and said it acted like a fuel filter; he checked and found a new one on it. He replaced that filter but it didn't help correct the problem. His suggestions; said the noise was probably a cam chain follower noise, a fairly common complaint. He said his next action would be to pull front engine cover and look for cam phase problem.

At this point I have decided that the problem can't be looked at until all the plugs are replaced with the proper ones.

At this time I am worn out and am going to take a break on this thing. I can and do drive it daily and it runs very well at a light load; just have to be carefull when passing.

John L.

 

I am having the same exact problem. I finally got a code from it. Turned out to be cylinder #1 misfire. I Haven't had a chance to look into it anymore.

Good Luck