Hey
So I recently purchased an 08 F-150 5.4L Triton, with 220k kms on it. It is an Automatic transmission. The problem I am having only ever seems to happen at low RPMS, and is hard to reproduce. At Low RPMS the Truck starts shaking, and makes a weird I guess "clunking" noise almost sounds like it's not completely in gear. Switching from the current gear to any other gear/park does not fix the noise. I have to shut the truck off and restart it and it goes away. I tried reving the truck once while it was doing it, and although it did make it stop, it did not sound nice when I did it. I have hauled heavy loads with the truck, and it had no issue driving while under load, although I never drive the truck at high rpms, with the high kms on it I want to baby it. When I first got the truck I changed out the fuel filter, air filter, and the fuel pump driver module. I took it to a local shop to have it looked over, and they were unable to reproduce the problem I've been having. They said there was an error code for the fuel pump assembly, but it could have been caused from changing out the driver module. I was wondering if anyone could help. Would a bad fuel pump cause this? I get a 40% company discount at lordo, so if it really is the fuel pump it would be cheaper for me to just buy a new one then have the local shop rescan the codes, the cheap code reader I have isn't throwing any codes.


Thanks for any help!

 

An intermittent 'rough idle' is one of about four odd ball characteristics of the 5.4 3v that will drive you plumb *@(Ck#**ing nuts and bankrupt you (even with your 40% discount) if you start throwing parts at it trying to "fix" it. The others are 1) the famous 'diesel' knock that sounds like a power stroke at idle. 2) the famous 'tick' that sounds like a tappit or exhaust leak at idle. 3) the random misfire that occurs around 45-50 in OD - ALL WITH NO CODES. Fortunately for us, three out of the four silly symptoms are at idle, and that represents a small percentage of our use. But there are plenty of completely inconsistent 'opinions' out there as to what causes and what will fix each of them. The common thread is they all cost lots of money and are generally ineffective.


The damn motors will run 2,3, or four hundred thousand miles all the while making the strange noises and funny idle. So my suggestion is do a thorough engine flush about every seven or eight oil changes, use only motorcraft filters with good oil, and run a can of injector cleaner through it about every oil change. Other than that, drive the hell out of it. It has worked for mine for over 200k miles and it has always, and still does, do all the above.


Hope yours is equally as servicable

 

Have you looked into the VCT solenoids and cam phasers yet? I really hate to send you down the rabbit hole I'm in, but the symptoms are similar with my 2008 Expedition EL.

 

Acknowledging Torque's wisdom, this sounds like it might be a slightly different issue with a not-so-great description from the OP.

Torque's item #3 is the only one that might apply here, but the noise you mentioned is curious... is it a one time "clunk" as if a hard shift, or is it a constant noise?

And are you sure it's a "clunk"? Most often the random misfires are described as a "stutter" and it feels like there's a momentary lapse of fuel delivery

How does the truck feel when the clunks occur? Misfires from COIL/Plug issues often feel a lot like fuel delivery issues (like a bad fuel pump driver module).

Maybe a better description would help us to figure out if this is just one of the adorable "characteristics" of our engine, or whether there's something more acute going on.

 

It's always only at low RPMS, and I guess it could be a stuttering noise. it is constant once it starts, not just one clunk, hence why I have to shut off the truck to make it stop. Although the problem is very hard to reproduce and does not always do it. It seems to happen more often after driving around and everything warms up, and then I let it idle after, but it doesn't always. What happens is when I slow down to an idle the whole truck pretty much starts shaking, and it sounds like a sputtering noise, but it sounds a little more aggressive then a staling out vehicle. The Fuel pump driver module is brand new, changed it because it was throwing an error code. It drives around fine, even under heavy loads, up and down hills no issues

 

Pretty sure by your description that you have a VCT issue. A lot of times, VCT solenoids can cause this issue, where the cam is not allowed to actuate to the position it needs to be in to idle properly and causes the noise you describe, as well as stopping once you rev it some.

 

Would a VCT solenoid through an error code?

 

Sometimes, yes. Sometimes, no. They usually will throw a code for example like P0340, P0344, P0345, P0349, depending on which bank is effected. But the symptoms alone you described say VCT issue. Plus, you said you hear noise when his happens. This is common on 5.4s if they are having timing issues, either due to the solenoids, or low oil pressure, since the whole VCT system is actuated by oil pressure and the solenoid controls the flow of the oil into the VCT chamber to advance or retard the camshaft timing. I would replace the solenoids and see what it does from then on. At that point, if it still does it; then you may need to get the engine oil pressure tested at hot idle to make sure it's within specification.

 

I seem to recall something about FoMoCo recommending a change up to 5w30 in place of 5w20 for the CVTs at hot idle?

Where did I see that?

Anyway ..... I know they told us years ago to go to 5w30 on our CVPIs and I've been doing so on my 5.4 as well since last oil change.

 

I changed the vct solenoids and the issued has gotten a lot worst, it does it pretty much constant now at warm idle. I damaged one of the old solenoids during the process so going back is not an option, any advice? I'm going to take the new ones out and make sure everything is all good with them, and change the oil making sure it's 5w30.

 

You most likely have an issue with your oil pressure. I run 5W-20 in my F-150 5.4 and have no issues with pressure or idle smoothness. Go ahead with the 5W-30 though. It can't hurt anything anyway. It might just raise the pressure enough to smooth out the idle. You probably have mechanical issues elsewhere though and even if the oil change smooths it out - can't say for sure how long.

 

Changed the oil, issue still there . See links to videos on my issue
Truck at normal idle:
https://*******/PC48
Truck in drive idle:
https://*******/rLKE
The Issue I am having:
https://*******/lX1v

 

That is the sound of cam timing being off at idle. Since the solenoids didn't work, the next step to take would be having the oil pressure tested at hot idle. Ford spec is 25 PSI.

 

This thread is beginning to sound exactly like this one.

https://www.ford-trucks.com/forums/1...ng-5-4-3v.html , and probably a hundred other ones on this and other forums.



@07F150Lariat5.4 , please know that I'm not attempting to be truculent or quarrelsome, but on what authority - or can you provide authoritative reference to this claim. It is a common claim thrown around on these forums but I have NEVER seen it in print any specification or authoritative form. The _closest_ I've ever seen is in the Ford Factory Service Manual engine specifications. It says: "Oil pressure minimum at 2,000 RPM (engine at normal operating temperature) = 517 kPa (75 psi)".

I have searched the subject pretty exhaustively looking for an OBD II PID for oil pressure (either published or unpublished) for the Ford 5.4L. OIL PRESSURE is so highly important for proper operation of the VVT system(s), and with all the emphasis on mileage & emissions (both beneficiaries of VVT systems), it doesn’t make sense at all - but it is absolutely non existent.

I would be willing to bet that not one in a thousand F150's (with over 10,000 miles on them) will idle at 25 PSI hot. (Mine will not). That is likely why Ford engineers have equipped them with the "idiot gauge" that reads just over 1/2 scale when the damn binary oil pressure switch closes.

It borders on fraudulent misrepresentation to take a mechanical switch closure (oil pressure SWITCH) designed to switch between 5-7 psi, and display the closed condition as mid-range on an "analogue gauge" on the instrument cluster marked “L” | “H”. Especially if it requires 25 psi for the VVT system to function properly at idle.

 

I have spoken to several Ford Techs and they all say 25 PSI is what Ford has specified. Ford recently changed their minimum hot idle pressure to 15 and I have no idea why, but most start knocking at 15-17 PSI.

I have an aftermarket gauge on mine and it idles at 25 PSI as well. It's ok if they are down to about 20 +/- as a friend of mine who just did his timing set idles at about 20-21 PSI in drive and another friend of mine who has 45k on a reman 5.4 that idles at about 22 PSI in drive and 25-26 in park. Mine is 25 PSI in drive and 27-28 PSI in park. All of these readings were taken on 5W-20 Motorcraft oil.

The readings at hot idle are all over the place with these engines, but there is a minimum, which like I said about 20 or so. But, if you are down to like 15, the pressure will not be enough to return the cam phaser sprocket back to full advanced at idle and that is what causes these cam timing codes. Many of these engines are replaced due to this issue. Common causes of low oil pressure are worn cam journals, blown tensioner seals and several 2007-2008 F-150 5.4L engines are replaced due to crankshaft thrust bearing failure causing the same symptoms. Low oil pressure, knocking/rough idle, etc.

VCT solenoids are also a common cause, but if replacing the solenoids doesn't fix the issue, then it is usually a mechanical issue in the engine.