Just got 2005 screw fx4. Seemed to run ok 115000 mi.Had exhaust leak,I put on 3" cat back on. Then I noticed tapping at front of engine .Turns out tim. chain guides broken. looks like very common prob after reading many forum/threads. Any way got timing chain kit, phasers, selinoids. Truck runs and sounds great.But so far had truck back 2weeks stalled 2x at idle.What next??

 

It is very likely the vct solenoids are sticking causing the stall. You having low idle rpm issues then stall or a stall out of nowhere?

 

It stalls at low rpm ,it idles at ~500-550. I'll be driving home(20miles),turn into my driveway ,slight grade, truck dies.the other time it died I was in park, shifted into reverse and she stalled.

 

My daughters truck is doing the same thing. I will suddenly idle down, and sound like a diesel. After 2500 bucks the dealer wanted another 1700 to "fix" it, I told her to bring it home and I'd give it a shot.
Where are the vct solenoids at? I'm assuming under the valve cover, they wanted a bunch of money to pull it off.

 

My truck is 2005. I think 2004-2006 the solenoids are mounted on top of the valve covers. Any way i already replaced them a few weeks ago.Next thing I'm thinking about is oil pressure.I just have a dummy gauge for oil pressure,so I'm not sure of real oil pressure?

 

Pick up a cheap scanner that can read live data to check your oil pressure.

 

Your going to have to tap into the oil filter adapter, pull out oil pressure sending unit and read from there. Spec is 15psi at hot idle but was 25 psi for years before Ford revised it. Oil pressure is a good place to start on these.

 

So install a sandwich adapter plate, and get a separate gauge? With a 'real gauge' I'm not sure what numbers to look for, or what to do next? Am I trying to diagnose a bad oil pump? I've been watching the stock gauge. When I start the truck ,the gauge goes from 0 to about 55% .But after that the gauge doesn't move when I let off gas or punch it... just stays at that 55% setting . I know I should see a drop at deceleration and move up w/ acceleration. One other question should I use something like Marvel mystery oil to 'desludge'.
Thanks
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Yes you need to use a real gauge, the oil sending unit on the truck is literally an on off switch and doesn't read pressure. So hence a scan tool will also not tell you. Check it when it is nice and hot when it is happening, I like to see 20psi hot idle accessories off. The pumps are usually ok it is all the areas on the truck that get loose tolerances and cause loss of pressure and vct system errors. You can use a desludge additive but if the oil pressure is the problem that wont do anything for you.

 

I got the oil pressure gauge installed, just ran it today.At cold start the pressure was at about 65-70.then when it gets warm and I going 45mph, pressure is at about 45-50.Then when warm about 20 min later , when I come to stop sign pressure drops to about 12-15. So my friend, who is a mechanic, mentioned using 15w40 oil to help with the pressure drop. I know I've read in several articles that changing the oil pump does no good.So do you think that is the case here, where a higher output oil pump would not help?I think I'll try the 15w40 and see what happens.I'm not sure what a 'sludge problem' would look like as far as pressure. I'm guessing all #'s would be suppressed?

 

Is your low idle and stalling accompanied by loud engine rattling? If not then it could be just carbon deposits in the throttle body restricting idle airflow.

 

If your oil psi is at 12 I would pull the pan and check the oil pick up screen for restriction.
When the guilds go all the crap sits in the pan and blocks the screen. Before you spend a lot of money, pull a cam cap if scored engines done.

 

I did clean the throttle body. When the truck stalls it has that diesel sound, I throw it in neutral rev it to about 2500rpm and it clears in about 5 seconds.So now i throw it in neutral whenever i come to a stop so oil pressure stays at about 20-25.

 

I'm just a 'shade tree' mechanic. The one thing I can't wrap my head around is if the engine is toast, why does the oil pressure stay at around 50psi while I'm driving.I know higher rpm will turn the pump faster and increase output. so if that's true why wouldn't a higher volume/output pump help? I can imagine how there could be crap in the pan (clogging screen) looking at what the guides looked like when they came out,in pieces. Wouldn't there be a decrease in pressure most of the time??

 

I just wanted to thank every ones input with this truck.This is aggravating ,just wanted a truck to go fishing and pull my little bass boat.