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Ford 4.6 nightmare/help

[EDIT] For anyone who had this come up on Google and is looking for a solution. This problem was fixed by replacing VCT soleniod(s).

After driving and slowing down, the engine cab get stuck in an advanced timing causing the motor to chug, lug out and sometimes die. The 5.4 can also have this issue.


I have a 2010 Ford F-150 with the 4.6, got it from a buddy of mine who was ready to ditch the ol’ boat anchor and get something new.

Rather miraculously he gifted it to me for free! Whether it was from good intent, malice, or him seeing a way to freedom, I am now the owner of a stubborn truck that has been the bane of my existence since I got it.

It was a utlity truck for what I think was an electric company and was purchased from a “reputable” auction for the low low price of $3500. After he got the truck, he saw it had 250k miles on it, and the A/C didn’t work hardly at all. He took it to his friendly neighborhood mechanic who took the dash apart in an attempt to help fix the A/C and discovered it had been in a flood. In just taking the dash apart he removed an entire 5 gallon bucket with of dried mud and dirt from the vents and behind the dash.

Now with working A/C, the truck started to have a few other issues a few months later.

  1. Loud clattering on start up. (Really bad in the mornings with a cold start and a little bad during warm starts.)

  2. After the engine was warm, it would loose power going down the road.

  3. With a warm engine, it idled really rough and will almost die. It did die at least twice. But if you rev the motor for a few seconds it will go away and idle smooth. Sometimes endlessly, and sometimes only for a few seconds and then idle rough again.

  4. Poor fuel mileage, fluctuates from 12mpg to 14mpg.

His mechanic went and replaced the plugs, coils, wires and put it all back together. Problem still persisted. He then gave the truck to me and bailed out of the situation.

The entire time he had it, it never threw a code. Never once. But it won’t pass an emissions test saying it has bad catalytic converters.

Now is where I start to mess with it. It finally popped a check engine light when going down the road and experiencing power loss like usual. It flashed then remained on. It’s still on and flashes every time I loose power.

It said that the cam shaft position sensors where bad. So I replaced them.

Drive smooth for about 5 minutes and started to whole problem over again. Said “scratch that” and did some research, found that a lot of people seem to have had this issue and it was a faulty alternator. Seemed kinda funny, but what the hell. I went for it. Replaced the alternator and ran like a dream! More power than ever before! No rough idling, power loss or stuttering. Even got up to 17.8mpg.

I felt like I had finally won, the truck had submitted to my superior will and intellect. Or so I had thought…

One day later, ALL the problems return and it’s all there again.

I know the clatter on start up is the timing chain tensioner. It’s shot from the number of miles and use and is letting the chain smack the timing case. But I know the timing isn’t off. It will idle endlessly for ours perfectly smooth till you go drive and get it hot. Might happen a lot, might not happen at all on some trips. It’s currently up to 280k miles.

So what’s next?

Plugs, coils, camshaft positions sensors, and alternator have been replaced. Every code keeps saying “missfire” on multiple cylinders and camshaft sensor codes again and again no matter what’s replaced. Am I missing something? Could the catalytic converters be messing this up somehow? Faulty O2 sensors that aren’t throwing a code?

Please someone help, before I end up in debt trying to prove to this truck that I am it’s master.

-Helpless or hopeless in Texas

Camshaft sensor codes and consistent timing chain noise lead me to think that the timing is indeed off. Especially since you already changed the cam phasers, ruling them out. I’m thinking there’s enough slack in the timing chain to cause timing to be out of whack, giving you the loss of power and misfires. It could be the timing chain tensioner, rather than the chain itself, that is causing the problem. If the cats aren’t restricting the exhaust flow, I don’t think they would cause driveability issues.

I could be wrong, I’m not a professional mechanic. I think you’ll probably have to delve into the timing chain a little further to fix the problem. May have to replace timing chain guides, tensioner, and possibly the chain itself. But given the high mileage, flood damage, and zero purchase cost of the vehicle, is it worth replacing all that? Probably only if you can do it yourself.

Again, I’m not a professional mechanic, so I’d seek the advice of one before ordering a timing set. I do know the timing chain guides and tensioner caused issues on the 3 valve 5.4 liter engine, and I assume the 3 valve per cylinder 4.6 liter uses a similar setup. It’s a common enough issue with the 5.4 that the aftermarket sells heavy duty timing chain guides and tensioners, along with a “lockout” kit to do away with the variable cam timing and keep the cams locked in one position. No more vct, cam phasers, etc. problems after installing the lockout kit. Livernois Motorsports sells one such kit. Might google them and read up on the kit and see if the issues you’re having sound similar to what the kit is supposed to resolve.

Also search “western motorsports cam phasers fix”. It describes the issue pretty well in their faq section.

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Before anything further, check compression if it has not been done. It ran good for a short time after alternator replacement with multiple missfires means that maybe there’s a faulty ignition module. I also like what @Scrapyard_John said about timing and cats. Another reason for multiple missfires is fuel delivery. You also need to clean all battery cables. Be prepared for neverending with a flood vehicle.

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If it was flooded bad enough to get 5 gallons of mud into the A/C system, I can only imagine what the exhaust system looks like inside.


Given the truck was flooded, remove and clean every single ground wire connection you can find. Pull apart every wiring connector and spray them with electrical contact cleaner.

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OP, you said timing isn’t off because it idles good. One thing to remember, the truck has variable cam timing. So it’s possible timing is ok at idle, then is off later when the computer expects a timing advance or retard and the phasers can’t provide that due to the fact they work off of oil pressure, which is lost in the top end of the motor to some degree with wear and high mileage. Something to research anyway. I’ve been around several of those trucks (mostly 5.4’s) that knocked or sounded a bit like a diesel either at idle or under load at low rpm. One idled fine, but would misfire or spark knock a bit and feel sluggish at low rpm under load. I would bet money the vct was acting up causing the timing to be slightly out of whack at that rpm range. The fact that your timing system is worn to the point where you can hear the actual timing chain slap around…along with the code you’re getting… I strongly suspect an issue in that area. Anyhow, read up on the issue a bit if you haven’t already. Lots of info on the web. The first 3 valve Ford’s were somewhat notorious for vct problems.

My brother in law ignored a check engine light (he said it pointed to a cam phaser problem, I don’t know the code) and destroyed the engine in a really nice 2010 f150 that was luckily still under warranty. Ford replaced the motor.

Then he traded it for a Chevy, hated it, and now drives a gas F250 haha.

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I’ll go ahead and look into a timing kit, everyone seems to agree on that. I didn’t know it had variable timing.

A vehicle that was in a flood up to the dash belongs in one place only, the junkyard! Get rid of it before stubbornness makes you throw money into it. Even if you solve the current problems, strange electrical problems will continue to pop up.

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Like NYBo stated, I also think you should clean all your engine ground connections and check all the electrical connections for the engine control. Make sure that the replacement alternator is still okay and not generating excessive AC ripple voltage, like the previous alternator was doing.

Since you have a high mileage vehicle that has been through a flood, you should really think of how much money you want to invest in it to try and salvage it. It could end up being a money pit.

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