I bought a '05 F-150 with a 5.4 with 112k miles on it a few months ago. It had been sold from an auction, looked really clean, and a good price. Not long afterward it started having issues with running rough at idle. That's when I found this forum and began reading. Tried different things but it only got worse and finally had a shop look at it. Cam phasers were not doing well. Not a cheap fix but more involved engine work than I had ever done so I had them do the work.

It ran fine for a few days and then the idle rumble came back slightly and the check engine light (CEL) came on. I read the code and it came back with a number that indicated air flow was an issue. Internet search said to clean the throttle body. Some threads on this site also said do the Mass Air Flow (MAF) sensor while I was at it. Much has changed since I used to work on cars as a kid. Everything has it own cleaner. I cleaned the MAF sensor with MAF cleaner. Cleaned the throttle body with throttle body cleaner (it was beyond filthy) and a toothbrush. Put it all back together (started late and it was dark by now) and took it for a quick run to see how it had improved. Instead of smooth, it started running even rougher, and within 100 yards went into fail safe mode. Now my mood is getting darker. Park it and go inside to watch the Aggies in their bowl game. Good game but the truck is still running rough and I am losing confidence in my ability to do simpler things on it. I get up the next day and run codes on it. It had three codes all pertaining to air flow or the throttle position. I am thinking I screwed up the throttle setting somehow when cleaning or maybe only put the MAF sensor in upside down (that seemed unlikely since the screws only seemed to line up in one orientation). So I open the hood to check the MAF sensor just in case and find to my embarassment that, in the dark, I failed to plug the MAF sensor back in. The problem was a loose screw holding the tools. I plug the sensor cable onto the sensor and take it for a ride. It runs great. Life is good. MPG is climbing higher on the onboard display. My confidence is returning even after humbling mistakes. After everything, I still love this truck.

So, now for the tune-up advice. The truck runs well but still rumbles slightly. Based upon everything, I believe it was well cleaned before it sold but maybe not fully serviced. Spark plugs were possibly never done. I intend to do a tune-up on it but do not know what has already been done so I'll assume almost nothing. The air filter looks brand new. The serpentine belt has nicks so that will be on the list. I am thinking of changing the following:

• Spark plugs
• Spark plug boots
• fuel filter
• serpentine belt
• PCV valve

Oil was changed when the cam phaser work was done. So the advice really boils down to a question:

1. Is there anything else I should consider changing or doing or cleaning?

Grateful for any advice. I have not worked on cars much in the last 30 years but am beginning to enjoy it again.

 

Hi Texan, Let me share with you , that I have a 2004 F150 5.4, with 154,000 miles on it, and after searching in here, and buying a parts house repair manual, it is one of the easiest engines you will ever work on, just calm down, and be methodical while working on it.
Changing coils, boots, fuel filter, and belt, are super easy. Notice I didn't say plugs, they are super easy also after you have done it once, but searching this forum and watching the plug tutorials will get you through it, I have a thread of my own even.
The pvc valves on a 5.4 are not your normal replacement type found on older cars. They are wired, and heated, and can be taken off and cleaned, but shouldn't be needed to replace.
Where did you get the advice to "change" the PCV valve?

 

Thanks ojai150. The idea to change the PCV valve was mine from tune-ups I had done before on other cars. I'll look into inspecting and cleaning the existing one instead. You mentioned changing the coils. I was going to leave them to avoid the expense of replacing them.

 

5.4 owners change out coils all the time that are good, I was just saying they are super easy to get out,...
I forgot to mention that Youtube, is a great source of repair tutorials

 

Good info about the coils. I'll focus on the other things mentioned. Thanks again for the help.

 

Change the VCT solenoids too. There's 2 of them located with the plugs. Kinda pricey at 140 bucks for the pair but many others have changed them to solve a tick issue. I have an 04 and mine rattled a bit on a cold start and developed a tick. Took me 45 min to do both and I'm not by any means a mechanic. Rattle is gone at start up and tick is gone. Plenty of old threads explaining what they are. PVC doesn't need replaced in these= weird but true. Be careful with the plugs, they break easy. Rent a ford plug tool before starting the job to be safe.

 

I re-read Texans post again, TYOGA, and I don't see anything about ticking or rattling,...why should he change possible fine vct solenoids?

 

Thanks for the advice guys. I read about the VTC solenoids (in FTE of course). They were replaced with the phasers. The truck is running well now. I only detect a little rumble and believe it still needs spark plugs. I ordered spark plugs, boots, and a Lisle tool last night. I bought a couple of cans of Kroil to use to hopefully loosen things. I have been reading spark plug removal threads, trying to sift the wealth of information. Now if the weather will just warm up here again.

 

I had a previous post where I had installed some E3.70 plugs in my '04 5.4-3v. BIG mistake they started missing after 6 months and ruined one coil. I returned my truck to the Motorcraft plug (SP-515). Runs good but I still have a slight pre-ignition problem on light to moderate acceleration on uphill grades.

 

Thanks for letting me know. I think I read your post when looking through threads. Anyway, I ordered the Motorcraft spark plugs. Now I'm going to run some fuel system cleaner through the gas for a tank or two to see if that helps before changing the plugs. This website and forum is a huge help to learn from and hopefully avoid a few obstacles. Thanks again.

 

I didn't see it mentioned but check/replace the fuel pump driver module (fpdm) it's a good preventive measure and cheap and easy. Just figured I mention it. Oh and check the foam seal on the bottom and sides of the air filter tray that's another common problem with these trucks, mine was basically non existent and I replaced it with foam for windows and doors from Home Depot it only cost like 2 bucks.

 

I'm having p0171 n 174. No leaks at all anywhere but I did see what you mentioned. I was thinking possibly that might be my issue as i have done, plugs, coils,injectors, driver module, maf, intake gasket, hose behind is fine and attached.
My ltft do not change from 29.7. Even with throttle open.
smoked the motor also and no leaks.
paid a shop to diagnose since I'm at a loss. They found nothing they said. I made them redo the diagnostics n this time had it in for 4 hours. Still came up with nothing.
do you have a pic of what you did to yours? I have no family on mine what so ever n cant tell where you place it.
Thank you for taking the time to read my issue.

 

I read somewhere that the PCV vale on the 5.4L 3v was permanently mounted in the valve cover and both have to be replaced. That was a forum so not sure if that was accurate or if it was a different year 5.4L I have the 2006 5.4L

 

The so called pcv is a baffle in drivers valve cover which leads to the vac intake . At the intake is a heater that keeps line from freezing around 33 degrees it comes on .
To the guy with the 171-174 code , you are running lean so too much air or maf wrong . You need a homemade you tube smoke machine , or your 02 system not right can check for exhaust leaks also /cracked manifold etc . Air may be bypassing maf .