Those with 5.4L 3V f-series trucks

[9svt8]

I have a 2008 F250 with the 5.4...and I'm stumped. I've searched/read many posts on truck forums, but wanted to hear from the geniuses here as well, since I've always received good advice and direction. My truck had developed a slight hesitation during hard acceleration...so I changed fuel filter, and it was a bit dirty. Drive all town mostly, and it runs great. I get out on highway... seems to run good, set the cruise and as soon as I start to climb a hill it started bucking and carrying on till it dropped a gear, then it smoothed out. I decided, might as well throw on 8 new C.O.P. I get all of those on, and fire it up and it sounds better, drive it hard and it stumbles really bad...backfiring and acting all unhappy. I check them all, they are tight and all good. Under normal driving, it's fine. Drove to work this morning... ran ok, not much stumbling but not perfect. On the way home...runs horrible. Through all of this, no CEL. I hook up my X3 and it reads nothing as well. This is driving me crazy, as there are no codes...and the severity of it is inconsistent as well. I'm wondering if it's possibly the fuel pump relay switch, or fuel pump....or something else I may be missing here.

Any possible help/ideas from you guys as always, is greatly appreciated.

 

[BLOWN9646]

Did you change the plugs?

 

[9svt8]

I haven't yet, it only has 70k on it...I figure that's next on the list, however I felt that if it were plugs...it would be more consistent. Am I wrong in that theory?
Not being a smartass by that comment, serious question.

 

[01GTB]

Does it crank normally?

 

[9svt8]

Fires up every time all the time and idles fine.

 

[01GTB]

Before you get too far along with the fuel system, see if it has a fuel pump driver module like the 5.4 F150s do. On the 150 it is located on the crossmember right above the spare tire.

My neighbor spent three weeks screwing around with his 05 F150, eventually changing fuel pumps. He's a mechanic and was at his wits end and about to take it to Ford. I asked him if he had checked that and he was not even aware of it. Turned out to be the problem. His eventually died in the road after a few weeks of running badly.

 

[BLOWN9646]

I haven't yet, it only has 70k on it...I figure that's next on the list, however I felt that if it were plugs...it would be more consistent. Am I wrong in that theory?
Not being a smartass by that comment, serious question.

I would have changed the plugs before the c.o.p's

 

[SID297]

Pour in some Chevron Techron fuel system cleaner. It might help and certainly won't hurt.

 

[mc01svt]

I put money its the cam phasers. They were notorious on those 3vs...


Go on f150online.com and search for it. There's tons of post on similar issues.

 

[Willie2]

I had the hesitation issue at 2000 RPM and some of the symptoms you described. I loosened the throttle body and cleaned it out. Make sure to get both sides of the blade. Mine was covered in thick black gunk at 120k miles. This cured my problem. I think the blade was hanging on the gunk or air wasnt getting around the gunk smoothly at that angle.

 

[01yellercobra]

You shouldn't have waited so long to change the plugs. Make sure you have the tool for removing broken plugs on hand. I have an Expedition, which has the same engine, and at 50K the plugs were done.

It's worth looking at the FPDM just because it's in a bad spot. I've seen pics of some that have corroded away.

 

[SID297]

You shouldn't have waited so long to change the plugs. Make sure you have the tool for removing broken plugs on hand. I have an Expedition, which has the same engine, and at 50K the plugs were done.

It's worth looking at the FPDM just because it's in a bad spot. I've seen pics of some that have corroded away.

An 08 model should have the updated heads that aren't prone to having the plugs break.

The cam phasers would be a good place to look.

 

[9svt8]

Well, I didn't wait too long...I bought it 2 months ago, lol. I knew about the plug issue and thought I was safe with this one, but after doing much research these past few days...apparently it was with build dates that occurred around 10/07 that got the updated plugs with the brown boot COP's. My build date is 5/07, and I have the black boots on mine...so lucky me, I have the crappy plug design.

 

[Coiled03]

Just went through this problem.

Changed the plugs, problem solved.

 

[2013 Laguna Seca]

Change the plugs,that will fix your problem. Early to mid builds still have the 2 piece
plug design.

 

[99BOSS]

I had a idle sometimes that felt like a miss going on and when I floored it on the freeway, you could feel it stumble, ping some, and then finally begin to pull. Then one day I got the flashing engine light which means misfire. I isolated the cylinder, put 2 new COPs on since the code said cyl 1 then cyl 2. I then ran a bottle of lucas through it with some 89 gas instead of my usual 87. Now Im back to 87 and truck runs great. I had severe detonation there for a day or two while I was diagnosing the prob. This is due to carbon deposits in the cylinders. These deposits build up while casual driving with a misfire that you dont know you have. I hardly ever floor my truck so this allowed a buildup. These buildups create hot spots that will detonate. So everyone needs to blow these things out from time to time. Plugs could be going out too. I still have my originals and Im at 66K miles. But new COPs and getting some carbon burned out fixed my prob.

 

[hotrodjcc]

I put money its the cam phasers. They were notorious on those 3vs...


Go on f150online.com and search for it. There's tons of post on similar issues.

x2... I would also change the plugs to rule that out.

 

[2013 Laguna Seca]

Sid is right,the phasers or vct sensors can go bad,usually do to a loss of oil pressure
inside. This will cause the engine light to come on due to an advance/retard concern.
Replace the plugs man,that will fix it for sure.

 

[9svt8]

I am going to do the plugs next. I am waiting for Monday to roll around and have a friend of mine who is a real good mechanic and who has done a couple of these before and has the extractor tool should any break. He said $80.00 to do them, I'm not arguing...lol. I just need to find out which plugs are best to put back in.

 

[Kenneth]

AUTOLITE HT1's would be your best bet.

Went through this with my son's truck, also changed the FPDM at the same time.

Ran perfect until he blew the motor (Dam Whipple).

Just ordered a new motor for it, not sure if he will put the supercharger back on or not right now. If it does go back on we'll turn down the boost some.