I recently bought an 05 FX4 and I am new to the site.
I have an intermittent issue, Here is the senerio:
In the morning or when the engine is cold it runs fine and has the normal 5.4 ticking.
Once the engine gets up to temp are when the issue begins. It will be driving just fine and sometimes when I come to a stop it will idle rough and begin making noise like the loudest diesel that you have ever heard.
If I rev it up to about 2 grand it will smooth itself right out and stay idling smooth.

Here's what I have done so far:
New cam phasers, new fuel filter, new cam position sensors, and new VCT,
cleaned the TB and MAF. All of this has helped in different ways.
The truck has 140k and the previous owner had the plugs changed.

Any suggestions

 

Any dtc codes?

It could also be this>>> https://www.f150online.com/forums/v8...ram-07m08.html

 

When was the plug change? If it was fairly early mileage wise, may be time for the second change. I would check the injectors and consider doing a plug change. Then, if still there, I would change the COPs.

 

They were changed around 120K.
I am planning to try the COP's. How hard is it to change out the injectors?

 

Not to hard.....

Release the fuel rails and carefully slowly pull them out....

Have rags down by the engine side you're working on to collect the excess gas....

Releasing the fuel pressure at the fuel filter helps also...

Here's a Supercharger .pdf that shows how>>> http://www.magnacharger.com/pdf/manual-FordF150.pdf

 

I've got the same problem now that you described... did you ever get it fixed? if so what was the cause? Thanks!

 

I have the exact same problem on my 07

 

https://www.f150online.com/forums/v8...uck-stall.html


Read this post it helped out my rough idle, takes just a few minuts to clean

 

Well I purchased my 06 xlt w/ 5.4 flex. last year with only 90k on it and at 92k I had a bad valve lash adjuster and lifter on #4 cylinder. while I was at it replaced cam phazer and all was good up until just today at 115k.

engine cold runs fine. after warmed to normal operating temp it barely wants to stay running. pulled codes right away to get:

P0??? - cam position sensor (bank 1) didn't write this down just cleared it

drove for about 5 miles just fine (mix stop n go and highway ) then it started up again. pulled the codes again got:

P0300 - random misfire
P0303 - cylinder 3 misfire
P0304 - cylinder 4 misfire
P0174 - system too lean (bank 2)
P0012 - Intake camshaft Position timing - Over-retarded (Bank 1)
P0174 - system too lean (bank 2) repeat

some direction would be great as I really need this truck for work thanks

 

First thing I would do is change the plugs (motorcraft plugs) and make sure you put the c.o.p.'s back in the same cyl they where in, and replace both front 02sensor's. And replace that cam sensor as well. Sensors and plugs are cheap compaired to a hole egnine.

If that does not fix it then I would move the c.o.p.'s in 3 & 4 to some where like cyl no's 1 & 5 and clear the codes and see if the misfire moves to 1 & 5. if it moves you have bad c.o.p.'s.

If the misfire stays in 3 & 4 then move the injectors in those cyl to different cyl's and clear the codes agian and see if the misfire moves .

When I had the P0174 it was a bad 02 sensor. Then later down the road after I installed my cams I had a coulpe of c.o.p.'s go, then after that it started random misfire,that turned out to be the injectors.

 

I spent Fri. night and Sat. pulling COP's and SPARK PLUGS... YEAH!!!!

I assume they're the originals as they were motorcraft with green lettering, and 7 broke... the one that did come out in one piece showed a 3/16" gap!!!
following the TSB. (BTW, I agree that they break on the initial 1/8 turn, bank 1 did after only 15 min of soaking with PB and they came out better than bank 2 which I let sit overnight soaking). I found it easier for me to work on by removing complete intake manifold (so my BIG meat hooks could reach the back cylinders).

anyhow, put it all back together (same COP's / injectors to the same locations) tonight using dielectric grease and electrical contact cleaner on all connections, spark plugs being AUTOLITE HT15. Of coarse anti-sieze on all plugs and bolts. Started right up and ran GREAT. Let it get to operating temp and still NO PROBLEMS!!! I took it for a drive 10 miles city (stop and go), then 10 miles interstate. NO PROBLEMS!!!... That is until I pulled into the drive at home and what would you know? Same KNOCKING-DIESEL-DON'T WANNA RUN-POS behavior. Pulled codes and NOTHING. No codes... waited... still nothing... shut it off and started back up. still idling rough and no codes.

Well, I guess the good news is that the plug replacement took care of a strange shudder I had on the interstate when it would kick down uphill. And definitely has better power and throttle response. That is until it warms up.

Now, if it codes again. I will swap parts to see where the problem follows as suggested.

 

also, the oil pressure gauge shows as good pressure (little past half) when it is acting up. I don't know prior history other than it was a 1 owner corporate owned truck. what I do know is that I am strict with maintenance. I only use motorcraft 5-20 syn blend oil and oil filters. oil / filters changed just recently about a week ago.

where is the fuel pressure check tap? I used the odometer self test mode to watch fuel pressure when primed and value stayed at 110-111 with no change. much rather have my gauge connected. Maybe I'm overlooking it (right under my nose). I'm just used to seeing a tap on the fuel rails.

 

Why did you put Autolites in it?

I sure hope you put high temperature nickel antiseize on the ground sleeves and NOT the threads.......

 

Ha, I retract that last bit about fuel pressure. It was late and I was skimming through the shop manual that I have and seen the fuel sensor reading. I was almost definitely sure my 01 showed fuel pressure. didn't even think twice about how it was the sending unit reading.

on another note: when I took the intake out it had a lot of fluid in the bottom of it. I think its the seafoam that I tried sending through the vac line the day before the plug change.

 

bad idea....

do a BG motorvac service or use chevron techron in the fuel tank.....