Garetty

The motor in my 07 F-150 has been acting up lately. It started randomly losing power upon acceleration so we thought it was the Cam Phasers. We got new ones and it ran like new for about 4 days, then started doing the same thing. Then we thought it could have something to do with the programmer on it (Hypertech MaxEnergy), so we returned the truck to stock, still same results.

So about a week after that, I was getting on the highway and my truck started shaking, it felt like I had a clutch that was engaging and disengaging, and the check engine light came on. We ran IDS (my dad runs a body shop on the side) and it came up with #1 Knock Sensor, so we ended up replacing both. That seemed to fix the randomly losing power issue, but now it just has no high rpm power whatsoever. I can floor it going up a slight hill at 70mph on the highway and actually lose speed. And I know how it's supposed to run.

Now today, sitting at a stop light, it turned green, and I started accelerating like normal, and it kinda loses power for a few seconds and the exhaust gets all raspy, then it just gains it all back. It did that a number of times today. And it still has no high rpm power.

I'm guessing it has something with the timing and it not retarding to get max power for some reason, but I'm not sure. We're just looking at options right now. Of course my dad know what he's talking about a lot more than I do, I'm still learning but I get more than the basic idea of how everything works.
We will either rebuild the top end of the motor and try and fix it, or buy another motor with about 30-40k miles on. (Mines at 90k now.) What would you guys suggest? Any ideas what could be going wrong inside?

I'm also thinking about getting a set of cams for it, just for a little power boost. I've heard about COMP cams, maybe the XTREME Energy Stage 1. Or Crane Cam Z-Cams Stage 1. I don't really want to mess with the computer if I don't need to. I think both of those will work with it.

vintageman

Have you started with the simple stuff like fuel filter? Are there any other codes? Has the plugs and COPs been changed yet, I have seen those bad without throwing a code. Before you start looking at the worst, like putting another engine in, look at the other things that keep the engine functioning like it is supposed to. Any noises?

Garetty

New fuel filter, we've changed the plugs and coil packs. Fuel pressure is fine. It has always knocked a little bit, but I only notice when I pull up slow next to a wall like the McDonald's drive-thru. There is a thing in IDS where it shows knocks or something while you're driving, they should be about even but it gets to where they can be about 400 off, like one side at 1100 and the other at 700. That's at about 5000 RPMs.

vintageman

Have you tried unplugging the VCT solenoids to see if the noise stops? Maybe unplug one at a time to see if there is any change. It will have a lack of power when they are unplugged but if you already have a lack of power, see if it gets worse and if the noise gets better. There are updated vct solenoids out that may help if this is turns out to be the issue.

Garetty

We have not tried that. We have seen with IDS that they are working, but we may still try it anyways tomorrow night.

lewissa81

Kinda sounds like the phasers are going out, for the same reason the original ones did. They rarely fail "just because." You probably have another issue causing oil pressure to drop. Could be the tensioners, the oil pump pickup screen clogged, the vct's screen clogged, or even the dreaded (but also rare) sludge syndrome. I would pull the VCT solenoids out and see if the screens are clogged first, and go from there. Does the truck rattle at start up, or sound like a diesel when warmed up?

tritonbullet

Is the rattle a big issue?

Garetty

I'll try to check some of these suggestions tomorrow night or this weekend. The truck does not rattle at start up, only when I barely accelerate going under 10 mph. Of course, that's the only time I can hear it, it may do it other times and I can't hear it. It does not sound like a diesel at all.

I don't think the rattle is that big of an issue, it's been the same rattle ever since I got the truck at 64,000 miles. Regular oil change every 5,000 miles.

lewissa81

By itself, not at first. It is an indication of either low oil pressure to the timing chain tensioners, or a tensioner that has failed. Every time it rattles, the chains are slapping against the chain guides. The guides are plastic and will eventually break. The broken pieces can clog the oil pump pick up screen, and that is definitely a big deal.
If it's been knocking and rattling for a while, I would replace all the timing components as soon as possible to try to avoid any major engine damage. These tensioners can fail causing low oil pressure to the head, which messes everything up if it's not caught in time. Your best bet is to use all Motorcraft parts (Dorman phasers are known to fail prematurely), and replace the timing chains, tensioners, guides, phasers and VCT solenoids at the same time. There are a bunch of threads about this issue. I suggest reading up on it.

alsatropine

iTrader: (2)

Have you tried cleaning the throttle body and maf?