My '98 F150 4.6 V8 runs fine when it is cool outside. When it is hot outside(above 90 F) and the motor is warm (after a few minutes of driving) it runs fine. But if I shut off the engine, run it to a store for a snack, and come back to leave the motor will not start. The motor sputters a little like it wants to start but the RPM aren't high enough. It gets stuck in a very low idle for a few seconds then dies. If I let the truck sit for about 40 minutes and cool down it will start up again.
The starter will turn and it is getting spark. I think it has to do with fuel.
Questions:
Has anyone else had a similar problem?
Is there some part of the fuel system that would fail due to heat?
-The guys at Autozone suggested that the fuel pump could be the culprit, but I have never heard of one failing from the heat.
Any info helps
Thanks
Kyle

 

Could be electrical too. My sister had an accord in high school and anytime it was hot and she had the windows up and went to fire it up it wouldn't. But if you let it air out it would fire right up. She was getting spark but no fuel. Googled it an it ended up being a relay that when it got too hot would not quite melt but lose contact. Just a thought.

 

Check the ignition module. some of these get heat soaked when sitting hot and cause an "open" in the electronics. Have replaced a few for the same reason.

 

I don't believe a '98 has an ignition control module.

 

Will it start if you give it a little gas? What about if you floor the pedal?

Sounds like you may have one or more leaky injectors.

Throw a bottle of Techron in the gas.

 

I have an identical problem with my 1998. Did you ever fix yours?

 

Fuel system. Always start there eliminate that. You need a gauge to test the fuel pressure. Do that first.

 

Thanks jethat. As it turns out. When I posted, my truck was at the dealer (had been for several days). After having it for a week the dealer finally called and said I needed a new fuel pump. Including diagnostics ($89.00) they want $1048 to replace the pump and fuel filter. That's a lot of money for a retiree. I paid the $89 and brought it home. I've been watching youtube videos and ordered a Haynes manual. Next thing is to get the correct size quick disconnect tool. I worked on my cars back in the sixties and seventies, so will (try to) replace it myself. I scoured the web trying to find a way to spent the $600 dollars they quoted for a fuel pump for my truck. The closest I came was on the Motorcraft site. It was $500 and change. That was probably the one they were going to use. The Mororcraft offerings were all complete assemblies. Disconnect and pull out the old assembly from the tank, throw it away, put in the new one, reconnect and done. I haven't decided if I want to go with the aftermarket equivalent of the Motorcraft for about $200 or use a pump, strainer and misc parts kit for about $100.

 

Look on RockAuto.com - They have lots to choose from and they're much cheaper. You don't have to replace the entire assembly. But they have them too if you wanted to go that route. About $100 for the whole assembly from Airtex. I've had no issues with their fuel pumps.

 

Thats insane! I haven't done it yet in my truck but in my GMC van that I've done twice its 300 for the part from O'rielleys. . I would try to get the best pump I could afford. The OEM motorcraft is $234.00 at Rock auto and cheaper pumps start at about $100 at rockauto. You dont want to do this again and the better pump lowers the possibility of that happening. I went with an airtex pump in my van and it only lasted a year before I was redoing it. Another piece of advice is keep your filters clean and fairly new. If the pump has to work hard to naintain pressure through a clogged filter its going to kill it..
Good luck!

 

Habitually running the tank low on fuel will also reduce the pump life. Avoid going below 1/4 tank if possible.

 

@SJS and jethat - I'll check out RockAuto. Airtex pumps used to be made in Fairfield IL. not far from where I used to live. I assume they come from China now.
@glc I'm afraid I may have the exact opposite problem. I try to keep it full, but only drive it a couple of times a month (haul off trash. buy mulch, etc.) I questioned whether my aged gas might have gummed up the pump. So before rescuing the truck from the dealer I bought a bottle of STP gas treatment. Then at the dealer and finding it started right up (early morning and cool) I poured the STP in the tank before driving it home. Now I just want to drive the tank empty before starting the pump replacement.

 

If you drive it that seldom, if possible I'd use a good name brand gas with no ethanol and put some stabilizer in it. Replace the fuel filter when you change the pump.

 

I finally replaced the pump. Got an Airtex assembly, dropped the tank and put it in. I have a bed liner and really no one to help so I didn't remove the bed. Been working in the heat for about a month with no problems (knock on wood).