Fink132

Hey all I have an issue that seems to be getting steadily worse over the past few months...
From what i can gather it happens when I am on a slight incline (such as pulling into a garage).
The truck seems to bog down a bit (as normally expected when idling uphill) but then gets this terrible chugging type of noise almost like the rad fan is trying to engage or is engaging but is catching on something. The truck also noticeably shudders like it is missing. If I rev the truck up or put it in neutral and rev it, the noise goes away and doesn't always return if subject to the same conditions again.
Hopefully this all makes sense as it is a rather difficult problem to explain in words.
I noticed it bad today when in stop and go traffic on an on-ramp that had a grade to it. RPMs at idle are around 570ish and the problem drops the RPMs down to close to 500 (truck tries to recover itself) but sounds like it's gonna stall out.
I should note that the truck will do this if on an incline when reversing as well

I have a catback exhaust and a K&N CAI and the problem has only started appearing in the past few months.

Thanks for any ideas

uzikaduzi

I don't know if this is causing this or even partially contributing but CAI's can make our trucks run lean if you don't get a custom tune for it... the stock one is technically a CAI and is capable of giving more air that it can handle to begin with

RA010223

This same exact thing has happens to me and it has not lately but I really notice it when I am just feathering the gas and backing up my travel trailer which is putting a load on the motor. I have taken a video of it and brought it to my dealer because I know duplicating it will be difficult and they had no idea. Since I bought the truck (2008 5.4l xlt with 80,000 miles) I have put 20,000 on it and the truck is bone stock. I have not done the plugs yet and the dealer has no record of them being done. I have asked a mechanic there and he said the plugs are probably going bad and I plan to change them soon. This only happens to me during the warmer weather because I am more likely to be "working" the truck. If I change plugs and don't have this issue this year I will try and remember to post back. It is very annoying and embarrassing when your backing your rig into your camp site and it starts shaking and chugging violently.

Fink132

Yep custom tune is installed already...

As for the plugs, I just put new plugs in mine and they have less than 10,000 Kms on them... No issues when the plugs were changed or before with the old plugs...

One thing I have done is run sea foam through it... Any thoughts on if doing this could make the plugs go bad??

RA010223

I have recently ran sea foam through mine like 2 weeks ago for the first time. If anything I would think it would help the plugs and possibly clean them a little. Like I said though I have not had this issue since like last fall and it is when I am going back and fourth a lot trying to back up my 28 foot travel trailer. A bump of the gas peddle and it goes away other wise I can put it in neutral and it will run like crap till it runs out of gas.

uzikaduzi

I've considered seafoam a few times and it seems that the people that use it, swear by it (other than people that don't know how to use it and hydro-lock) and the people that don't have a lot to say negatively about it. there also doesn't seem to be a concensus on how or what it's actually doing... is the white smoke actually from burning off all the carbon or is it just the seafoam it self burning?

i have a couple of concerns... 1 I don't know how easy it is to suck too much in the vacuum line and hydro-lock, 2 is it actually cleaning anything, 3 is it cleaning in a safe way and not damaging gasket material or seals, and 4 could it/does it gum up o2 sensors or cats? but i have zero experience with it.

I would check for trouble codes

Fink132

^^I have never seafoamed like that...rather just put in a can and a half when I filled gas.

The truck throws no codes (gryphon programmer that is dash mounted)

hld247

Fink...does your issue happen all the time while going slow or only after the truck is at full operating temperature?

My g/f's 07 F150 has a similar issue where we pull into a driveway or put the truck in reverse on an incline and it starts running really rough and almost stalls. Reving the engine in neutral usually fixes it until you shut off the engine or start moving again. One time I left the truck running when it was idling rough and didn't apply any gas and finally got a check engine light (p0345 camshaft position sensor A circuit bank 2).
We only experience this issue when the truck has been running for a while (over 30 mins). I tried monitoring the oil temp using my edge evo but her 07 doesn't have the sensor in it.

We have replaced the fuel filter and spark plugs with no change. In doing research I found that the 5w-20 oil might be running thin and not lubricating the phasers correctly at low rpm/on an incline. I ran a can of seafoam through the oil and will be changing to 5w-30 this weekend to see if it helps.

Let us know if you determine the root cause of your issue.

Fink132

hld247, I pulled my dtc this morning and have the exact same code you describe. Let me know how changing your oil viscosity works

IceFishinFool

Fink... I had the same issue with my 07 5.4 and it turned out the be the VCT solenoid and that bank where you get the code from. My advice would to replace both VCT with the new current updated one. Stay away from the dorman brand as they are known to fail. I used the dorman VCT and they failed and ended up having to put in a new motor at 150k because it ended up leading to no oil pressure up top to the motor and there was all sorts of stuff that failed. Just my 2 cents worth. Might also check the chain tensioners, guides and phasers and as well as they could be shot