tried this in the modular forum with no luck, so we'll try here:



strangest thing happened with the truck in sig yesterday.

first a precursor; i generally drive like a total grandpa, never really getting too close to the floorboard with the accelerator pedal. also only drive 7 miles each way to work and back during the week, empty. this weekend i pulled a small enclosed trailer a couple hundred miles saturday morning, and did a couple "spirited" runs after unhooking later in the day, for no reason really. nice to remember what she's capable of, ya know?

well anyways, yesterday (sunday) after backing into my inlaws' driveway with the family, i could feel a very noticeable miss from the engine as i went to put it in park, as well as hear a noise... so i open my door, then the hood, and there is an awful knocking coming from the engine to go with the miss. i touched the gas pedal just a bit and it immediately went away, idled back down smoothly, and never had any sort of indication it ever happened after that. would have taken a video but didn't want to let it go too long like that.

couldn't pull any codes with the scan gauge.. and all has been fine since. (as a side note i have been chasing a very slight miss at idle all winter and spring.. has 8 new plugs, a cleaned throttle body, vacuum system inspection, air box foam replacement, and the MAF looks good.) i watched some videos on youtube about the cam phaser noise, and this sounded nothing like that.

what the heck?

 

a scanner might find it. might be a coil going bad.

 

in chasing my less-significant miss at idle i have done a cylinder contribution test with AE, and there was no clear culprit. and it's been over a week now since my OP issue with no signs of it reoccurring.

 

revisiting this.

towed my boat a couple hundred miles over the holiday, truck ran great. upon arriving home and backing it in, with the truck in gear and not moving/no throttle applied, i was getting a shaking throughout the truck, not as violent as in my original post, but very obvious. taking the load off the engine/bringing the idle up remedied it, but i could recreate it two to three more times... and then it was gone. my minor misfire/shake/what have you i mentioned in my original post is still most noticable with the truck in gear and foot on break (aka: low rpm).. put it in neutral and it seems to smooth out. no other driveability issues through the powerband.

still no codes. and running like normal two weeks later. seems like this only happens after working the truck. all the while running 5w-20 and Motorcraft oil filter. i can't convince myself its COP related, and all plugs were replaced in november. any thoughts?

 

Most likely, that knocking sound is going to be in your VCT. Your camshaft is probably not returning to idle position once the engine is at idle. Sometimes, replacing VCT solenoids have cured this noise and that shake due to the timing being slightly off at idle. It makes me think though that yours could be related to oil pressure as well. You said it happens mainly when the engine has been under load. As the oil gets hotter and hotter, oil pressure drops. Your oil pressure may be dropping too low at times to return the cam phaser to idle. These are just some guesses I'm throwing out here, but this has been known to happen.

Does it sound anything like this truck?

 

if i recall... it sounded exactly like that. i posted today with a feeling it may be VCT related as i've been thinking about it a ton, and i think you're on to something. maybe it's time i monitor my oil pressure. thanks!

 

also to throw in the equation; when gently accelerating, my truck has always acted like something is sticking and then finally letting go, making the truck surge forward a little. i cleaned the TB and MAF, since they were my first inclination to that issue, to no avail. wonder if the cams aren't advancing/retarding like they need to under light acceleration? interesting.

 

I am almost certain that is what it is. You could have a VCT solenoid trying to stick on you. They are notorious for it - especially with some miles. If it does it again, I would start with replacing the solenoids and it is very possible that could fix it. Been a lot of reports of the same issue being fixed with VCT solenoids. Otherwise, it would be oil pressure issue to the cam phaser possibly due to blown timing chain tensioner gaskets, among other things.

 

kind of ironic, but.. i did notice my info display flashed "low oil pressure" juuuust long enough to be able to read it when i started the truck this morning, then was gone. also been reading and it sounds like the VCT solenoid removal on my '07 will be a chore. bummer.

 

That is normal. Mine has done the same thing before. Usually it does it if I leave the ignition on for about 5 seconds before I start it.

The VCT solenoids can be a job. It used to be '04-'06 trucks you could remove the solenoid through the valve cover opening. But now, the opening on the '07+ year valve covers... the opening is smaller and you have to remove the cover to remove the solenoids.

 

ha, well good, i did happen to have the KOEO for a few moments before i turned it over.

so i read. sounds like i need to discharge the AC too, i'm not excited about that.

 

I have heard some people said they were able to remove the passenger side VC without discharging the A/C line. A (VERY) tight squeeze, but they got it. I'm not sure myself though because I have never had to remove valve covers on my '07 5.4L (and hopefully won't, lol).

While you're at it though, check everything when the cover is removed. Check the timing chain around the phaser to make sure it is tight and no slack. Also check the wear patterns on the camshaft lobes. Any scoring on the lobes could be a failing rocker arm. They usually make a lot of noise, but I'd check anyway, especially with the work it takes to get to them.

 

just a word of advice, it doesn't hurt to run a check over your lash adjusters and roller rockers while you have the valve covers off.

i have an 06 that also shakes at hot idle, especially in gear stationary. however my 'tick' is more prominent at the rear of the valve cover, making me believe it is an adjuster or rocker issue.

generally speaking, the passenger side tends to be the first side to fail, whether it is a solenoid, phaser, or adjuster, as oil flow reaches the front of the passenger side last.

i wish you luck in your repair, and i hope you can get rid of the tick- this might be a stretch, but i have heard of a simple oil and filter change fixing pressure issues- didn't work for me though!