Ok, I havent been around these boards much in the last year or two because I have been super busy with work, but I'm in dire need of some help diagnosing a problem with my truck.

Its a 2001 Supercrew 4x4 5.4L with 104k miles. All routine maintenance performed as it should be. Full synthetic run in it since new, changed every 5000 miles with a fresh filter. The typical 100k scheduled maintenance was performed at 85,000 miles - fuel filter, tranny flush, fuel system cleaning/flush, radiator system flushed, plugs and boots changed, etc. (all of this by a Ford Dealership tech - the shop foreman actually...he does my work on the side at his house). No known problems prior to that or immediately after.

Fast forward to about 18 months ago. My truck starting having some very intermittent starting issues. Occasionally when I got in the truck and turned the key it wouldnt start on the first try - it would turn over like nothing was wrong, but wouldnt actually start. I would turn the key off and try again and it would fire right up as if nothing was wrong. This problem became more and more prominent as time went on. I spoke to my tech about it and he said it sounded like the fuel pump check valve and that we needed to replace it if it got worse, which it would. Well it got worse, eventually where it would do that a couple of times a day, but never got where it happened everytime. He replaced the fuel pump about seven months ago. He said the pump was absolutely trashed - as in it was in pieces. He also replaced the fuel filter at the same time.

All was well for a week or two, and then all of a sudden the same issue was back. I called him and he told me to keep track of when it was doing it, and the circumstances around each time it happened (first start of the day, restart with only a few minutes of downtime, sitting for hours, rain, etc.). I started watching it and it gradually got worse over the last few months. This whole time its been doing the same thing - turn the key over and the engine turns over, but never starts. Turn the key off and try again and it starts right up. Then a few weeks back a new symptom develops. If the truck doesnt start right up, then the second attempt will actually start, but it would hesitate and stumble and act like it wants to die unless I give it some gas and sort of feather the throttle a little. It would come out of it and be fine at that point. This got worse and then two weekends ago, the truck started fine one saturday morning. I drove it to my warehouse and came back (15 minutes round trip). I let the truck sit for a couple hours and then tried to start it and it wont start. It will turn over, but wont start no matter how many times I try. I tried it thirty times and still nothing. My tech says check things like the air filter (based on the choking hesitation symptom that had started recently) and then the fuel pump relay. I replaced the air filter after checking it because the plastic nose cone had come off of the filter in there and was loose inside the air filter housing. I put a drop in K&N filter in it. The truck still wont start. I attempt to remove the fuel pump relay and cant seem to get it all the way out (it was getting late and I was tired, hands were greasy, etc) so I just pushed it back in place and closed the hood. Before I went in I wanted to check to see if the fuel pump was running when I turned the key on, so I had my gf turn the key on and off a few times while I was under the truck - sure enough I could hear the pump running so I told her to try and crank it. It cranked right up. So I figured me jiggling the relay did something, so the problem must be the relay. I went and picked up a new relay from the dealership and waited to install it for a few days because the problem went away. When the starting issue happened again yesterday I went ahead and swapped the relay out and everything seemed fine. I get in the truck today and it starts fine on the first try. I drive six minutes away and park for about 45 minutes. I get back and try to crank. The problem is back, and it takes three attempts to get it to start.

I'm about to pull my hair out - what else could it be. My Ford tech is lost - I am going to drop my truck off at his shop, but he said it could take some time to figure this out. I really don't want to be without my truck for a month while he tries to isolate this problem (I know I dont have a choice, and I am going to do it - just looking for suggestions I could give him to speed things along).

Thanks for any insight you guys can give.

 

I had a similar thing happen on my 2001 Screw and it got to the point where I was driving with both feet (on an automatic) pressing the break with one foot and keeping the truck from dying with the other foot. I found that the Throttle Body was ridiculously dirty and got it cleaned up really well with a kit and then ran the engine at 2500 RPM for a minute or so and got a bunch of black smoke out of the tail pipe. It's been running great ever since. I hope this helps, it may just be that and isn't hard to clean out.

 

Sounds like an idle air control valve to me man. Its dirty and getting stuck. I am almost willing to be money on it actually. Take that sucker off and clean it real quick. Should be right on top of the intake and will have two bolts holding it on. There is a little pushrod inside of it with seals around it that actually determines how much air goes through the intake and what not. If it is not running right then it will kill the truck. Trust me, just take it off and spray some carb cleaner in there and let it sit for a little bit. Then flip it over and spray it out with some compressed air and watch all the carbon and what not come out. If it starts doing it again then you might need a new one. Which is not bad, because they are only like 65 bucks. Sometimes you can clean them and they will be okay for a good while after, and sometimes the "innards" just get worn out and they check out on ya.

Worst case scenario, if I am wrong. You havent harmed anything by cleaning it.