Hi all new here. Been reading around and I think I know the issue but want to run it past you guys.

A little over a month ago my truck suddenly stalled on me, it restarted fine but had really rough idle and stalled a couple more times. I had drove about 10-15 miles before it did this, ran perfectly fine up to this point.

I got it back home and ended up changing the VCT solenoids as suggested on another forum. I also changed the spark plugs which i was already going to do. Truck ran fine after replacing the VCT's (Got them from Ford), Thought it was fixed.

Fast forward to today, about that same place in my morning commute as the first time the truck stalled, restarted fine but ran rough and had to keep my foot on the gas at a stop to keep it running. Ended up on the freeway and it drove fine for my 30+ mile drive to work, when I got off the freeway and the truck was back to an idle at a light the rough idle was there again and was trying to stall.

Do you think it could be the phasers that are causing the issue? I do not hear the loud clicking or "diesel" noise from the phasers. I was also thinking throttle body but don't know how likely that would be.

Of course no codes. The truck has about 99k on it and I drive about 80-90 miles a day to and from work so it gets used, I just want to fix this for good.

 

No. The phasers don't "cause" this issue. Low oil pressure causes all this mess. Sounds like you have caught this early, but low oil pressure from a clogged pump pickup would no doubt break down the little bit of oil getting through--hence, the crudded up VCT solenoids--as if 5w-20 doesn't break down rather quickly as it is (a silly idea = not using 10w-30 or 10w-40).

So, I'd probably ASAP pull that timing cover and oil pan and see what has grenaded already.

I'm under the assumption (gasp) that you know the maintenance history on this truck and a previous owner hadn't just slapped phasers in and hoped for the best while ignoring the oil pan itself. Either way, this is a way pricier outcome than something like a FPDM or TB unit, so at least eliminate that ASAP.

 

Before doing anything else, I would clean the throttle body and the MAF. I would also check the injectors for leakage.

 

Thanks for the replies.


The issue has not returned since last Friday. However I have noticed some odd throttle issues when doing a cold start and while taking off from a stop. On start the engine will rev up to about 1500 rpm, then come down to around 700 then back up. and sometime while driving I notice that the engine seems to be lugged down almost like it's taking off from a stop light in 3rd gear or something but when I back off the throttle and get back on it it's fine. While this is happening the engine idles ok and does not try to stall. This also is intermittent.


I should note that when the problem was occurring the oil pressure gauge on the dash never dropped below its normal reading which is just above midway on the gauge. When I changed the VCT solenoids I did not notice any debris in the ports or any varnish on the VCT or any other components in the valve train. The engine looks like it was new. I also did not notice any scaring or overly worn spots on the cams or any other components. That might not matter but thought I'd through that in any ways.


I am going to clean and inspect the throttle body this weekend, and see how that works out.

 

The oil pressure "gauge" is an idiot gauge - it won't drop out of the middle till the pressure gets real low - I think about 6 psi. I believe the phaser system needs considerably more than that.

 

Does anyone kn ow if you can buy an OEM coolent tree replacement if that is all what is damaged?

 

Try tascaparts.com.

 

Your stalling is from your TPS in most cases replacing your throttle body fixes that problem

 

Ok I also know this thread is over 8 years old at this point, but I just ran into this problem on my 4.2 v6 2003 XLT.
I don't think the fix is anything anyone here has brought up because I did everything including replace my injectors. I also went to the back of the truck and found dry rotted vapor hoses at the canister. I also found 2 other dry rotted hoses 1 at the firewall near the canister purge solenoid and a small 3" hose connecting that down tube to the straight line tube along the frame inside the driver's side wheel well. After addressing the vacuum compromised hoses I still had the issue so I concluded that it's either bad gas, a bad fuel sending unit, or a bad fuel pressure regulator on the passenger side fuel rail of this truck. The later models have the regulator on the driver's side. I have a youtube video here talking about the issue.
this video shows where all the compromised hoses are:
I hope I was able to help you out because at first I too thought it was a bad maf sensor, and dirty throttle body/IAC valve but it wasn't.