HI- I have a ford F-150 XLT 4x4 with an automatic tranny and it is a 4.6L V8. Year is 1998. This vehicle has never had any issues besides a new alternator. But now the vehicle dies while slowing to a stop in the summer. This does not happen in the winter. It happens after we have been driving for an hour or 2, then we come to a top sign and start slowing down and the engine dies. The engine will restart after sitting for about 10 min. If you try and start it sooner it will just crank and sound like it runns on 1 or 2 cylinders, and will not start. when you do get it started it runns normal and we can make it another 15-25 miles and it does it all over again. It is like somthing is getting hot because it doesnt happen in the winter. All the gauges are in the "normal" range. This issue doesnt happen every time you drive it but every now and then. The dealer can not figure it out or Ford motor company. Any ideas??

Thanks!

 

Get a fuel pressure test gauge and see what is happening to the fuel pressure.

I suspect you'll find its dropping off.

The other possibility that comes to mind is a failure of the fuel tank to vent properly, usually due to a faulty gas cap. Next time it stalls, loosen the cap and see if you get a woooosh of air into the tank.

Steve

 

Thanks for the ideas, they sound plausable...I will check in to it.. any more ideas?

 

Change the fuel filter if it hasn't been done in a while for sure. It certainly sounds like the old "vapor lock" type of situation or something in the fuel system. I love that SeaFoam stuff. A can of that through the tank might be good also.

 

I checked the fuel cap and it appears to allow air into the fuel tank. I sucked air through the middle of it and i also compared it to another fuel cap.. why does it just do it in the warm weather...pulled fish house with it all winter and no problem but now the boat and there you sit on the road...no codes in the computer....it just shuts down like you turned the key off, no sputtering or anything. You dont even really know it died until you lose your steering....thanks for the info so far guys!

 

Well, I wasn't actually going to make the suggestion to test the cap that way, but it is a valid test. Hope no one saw you doing it so you'd have to explain it...

Here's a couple of ideas on what might be causing the problem: Fuel pump or its electrical feed is flaking out, crank sensor thermally intermittent, intermittent ignition switch or one of the critical relays (ie, fuel pump or PCM Power).

As you can see, there really isn't much in the way of data at this point to provide a definite direction....

Steve