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F-150 dies and won't start for 20 minutes

I have 1999 Ford F-150 2WD Lariat with a 4.6 liter fuel injected V-8 engine. I’m the original owner. It has 77K miles on it and is driven about 3K miles a year for the last couple of years. It sits a lot because we have three cars and two drivers in the house. I’m a Scoutmaster and use the truck for towing the troop trailer for our monthly outings. These trips can be as short as a few miles or several hundred miles. When it isn’t towing the trailer it is doing short trips to the home center or taking my son and the lawn mowing equipment a mile or so to the other side of the neighborhood for a lawn mowing job.

Three times now, once in April and twice this month it stalled while I was jockeying the trailer around the parking lot at church. The first time it had a full tank of gas and was at the beginning of the trip. I unhooked from the trailer and used another truck for the weekend. When we got back it fired right up and had been running fine ever since. I changed the fuel filter, added some fuel cleaner and unrelated to this recently replaced the battery and air filter. I didn’t have any problems with it again until last week. On Sunday we returned from our outing, about a 1/4 tank of gas in it, the trip was very short, 7 miles to the camp site. After dropping the kids off at one parking lot, shutting the truck down in the process I drove over to the parking space for the trailer and backed it in. While I was unhooking it it stuttered to a stop again and wouldn’t start. I let it sit for about 20 minutes after opening the hood and giving it a good stare and it started again. We swapped the fuel pump relay with another identical but unused relay (trailer battery charge circuit) but that didn’t make a difference. Last night it happened again, and again after 20 minutes it started fine.

On all three occasions the common thread has been short drives followed by several times of starting and stopping the truck as we moved the trailer from one place to another. The last time I shut it down normally and it wouldn’t restart, the first two times it stuttered and died while idling.

It has plenty of crank, and it sounds like it is firing but not getting fuel. Both times this month after letting it sit for 20 min it fired right up and idles and accelerates fine.

I don’t get any “check engine” lights so I’m not sure if the mechanic will get anything from the computer. I’m due for inspection next month so it will be going to the shop and I’m sure it will work fine while its there. I don’t want the mechanic to just start swapping parts as some will wont to do.

Given the prime use for this truck I really need to get it fixed right the first time. I can’t have it die on an outing and have us stranded in the middle of nowhere on the way to a camp site. Any ideas guys?

Does The Truck Have Any After Market Electrical Equipment Added, Radios, Remote Start, Alarms, Etcetera ?
Any “Theft” Warning Lights ? Are You Using A Ford Key And Not An After Market Copy ?

Some 1999 - 2001 F-150s (and other Ford models) can develop problems with PATS (Passive Anti Theft System). On some of these vehicles the PATS will shut down the fuel injectors/fuel pump.

Sometimes cars “think” you’re trying to steal them when something in the system goes amock and they hibernate for a period of time.

Usually the PCM will store a code P1260, but you would think that the “check engine” would illuminate.

I’m just throwing this out here for consideration if other regular diagnosis doesn’t turn up anything, like a failing fuel pump.

CSA

I’m leaning towards a fuel pump, but I’ll keep that code under consideration. But as you point out it would likely lead to a check engine light. I think either Autozone or Advance Auto will put a computer on the truck for free so I could have it looked at before I take it to the shop. I use an independent shop, any reason I should opt for the dealer on this one?

Thanks for the input.

CSA,
I was reading some other unrelated threads here and noticed you mentioned on one of them that the fuel pump on another car isn’t monitored by the PCM but can be tested at the shop. There is a tire valve like port on the firewall for the fuel system I assume this is where it is tested. Since I don’t have the equipment I’ll leave this to the shop, but I assume the fuel pump on this isn’t monitored by the PCM as well and testing at the port will likely tell me if the fuel pump is a bit dodgey.

“Does The Truck Have Any After Market Electrical Equipment Added, Radios, Remote Start, Alarms, Etcetera ?
Any “Theft” Warning Lights ? Are You Using A Ford Key And Not An After Market Copy”

No, everything on this vehicle is factory original. So can the garage tell if the fuel pump is on the way out if the truck is running and starting OK when I take it in for service?

Question. When the truck stalls and dies while idling and will not restart are you trying to restart it without depressing the accelerator pedal?

Correct. When it starts normally I never need to press the accelerator pedal either.

The next time the truck acts up depress the accelerator pedal and try to start it. If it starts up then there could be a problem with the Idle Air Control Valve, clogged IAC passages, or (less likely) an electronic problem with the IAC wiring. This is not a rare problem no matter the make of car and the sparse use of the truck can contribute to Idle Air problems.
Basically, things soot up and get grungy and like a chimney sweep cleaning out a fireplace and chimney sometimes the IAC needs to be removed and things cleaned out.
In some cases a new IAC may be needed.

I would also advise checking for a vacuum leak at the same time. This is a very simple procedure and only takes a minute. The IAC is a vacuum leak of sorts but it’s a computer controlled one; at least when things are working normally. Hope that helps.

Thanks for the response. When the truck does start it does not idle rough or have problems accelerating. Wouldn’t the vacuum leak or IAC problem show problems when it was running?

Carry a can of starter fluid with you so when the trouble happens again you can spray some fluid into the intake and see if the engine trys to run. If it runs for a short time then you have proved the trouble is due to a fuel delivery problem. If it doesn’t run then the trouble is most likely with the ignition system. From what you say I tend to think you have an ignition problem here. Checking the power to the ignition system would be the first thing to do if that is the case.

To me it sounds like it is firing, but I think I have a can of starting fluid so it won’t cost anything to try your test.

ok, simple “Gas” or “Spark” determination.

you need 3 things for your truck to run.
Compression (air being compressed)
Gas (something that burns)
Spark (at about the right time…)

get those 3 things and the car will do something.

get a can of spray atarting fluid.

when it refuses to start - spray some starting fluid into the air intake (air filter in a pinch)

you are giving the truck gas.

If it acts like its fixed - and starts fine, you are not getting gas at startup for some reason.

if it starts and dies, you know its not getting gas.

if it does nothing - its something with spark.

I would also check the battery connection. common problem is the coil pack not getting enough power and not firing a spark. give it more power by connecting the battery properly.

I think you’re just getting flooded. You describe the issue as coming up after short drives and then a lot of starting / shutting down. This is a good way to flood the engine, especially if, say, your plugs are rather old & maybe your thermostat/coolant temp sensor as well. The way to find that out is to floor the accelerator pedal while you’re cranking. That’s a flood clear so if it helps get it running then I’d stick with the flooding assumption.

I also think its possible that you IAC is acting up intermittently, maybe especially when on the cooler side. If that’s so a good cleaning would help.

The battery was just replaced 3 months ago after the first time but before the subsequent times. The first time it happened the connections were in need of a cleaning which I did after it decided to start 2 days later. I now have a can of starter fluid in the truck to test the fuel theory. It is probably time for new spark plugs and wires, which I’ll look at doing when I get it inspected.

The IAC may not show any symptoms once the truck is running. A vacuum leak may not be noticeable if it’s a small one but a larger leak should show up as a rough idle to some degree.

The fact that depressing the pedal to get it to start could be an IAC fault or as mentioned, the possibility of flooding due to a leak. Generally speaking, when a flooded condition exists the engine usually runs a bit ragged upon startup.

Update. Last weekend it died once again and I was able to get it to run on starting fluid. Pressing the gas didn’t do anything when it was running. This time it wouldn’t start even after sitting all weekend. I had it towed to the shop and it turned out to be a bad fuel pump. Thanks for the ideas guys, I’ve been carrying a can of starting fluid in the truck for the past couple of months waiting for it to die once again. The truck does sit a lot as I only use it for trips to the home center, transporting my son around for lawn jobs and scout outings. If I don’t need truck capabilities it stays home.

Replace the gas pump, imho. Sorry posted before reading the update, glad you are up and running!

I always hate to hear that I had it completely backwards, but I surely appreciate the follow up. They are all too rare.

Cig I hear you, great to have a followup, cars have so many potentials for problems, and over the internet is much more difficult than a real world car in the garage, I speak for many in appreciating your continued contributions.

Cig, I know what you mean on the follow-ups. I don’t hang out here very often but do on a home improvement board. It’s rare when someone comes back to say, hey thanks for the advice. From the first time it happened until it finally died and wouldn’t start was 11 months, though in the 11 months it probably was only driven 2000 miles, tops.