Been having this issue for a while. Truck runs great as long as above 30 degrees. If it gets cold, truck won't start.

1st off , 2001 F150 4.6L, has 160k miles. I have been putting heet in the tank for the last month or two. The tank is FULL of gas, and I replaced the fuel filter a couple of weeks ago.

I have figured out if I do the turn key 3 times things before turning over the engine, I hear a short buzzing sound each time which i assume is the fuel pump. When I hear the short buzzing, it always starts.

Yesterday, it got cold again, and the short buzzing sound was more of a quick click/clunk, and it did not start.

Today, it got above 32 degrees, I did my turn key 3 times and I heard the short buzzing each time..............I pretty much knew it would start and it did.

So anyone have an idea why things don't want to work in the cold? I am hoping its not a fuel pump (can't understand why it would work when warm, and not when cold)

 

Mods to move this to V8 engines or 97-03 section

Sounds like the fuel pump giving you trouble

I would be checking fuel pressure

 

So it cranks over fine but has trouble starting? It does kind of sound like a fuel pump.

-Steve

 

Took it to Meineke, they assessed the issue as a bad battery. Never had issues with the engine cranking, but apparently it was supposed to be pushing 850 amps and was only doing 550 amps. The temperature change would explain the battery performance.

I am skeptical that its fixed, but it was 6 degrees today and it started on the second or third try.

 

Factory battery would have probably been a 650 amp 65 series battery, Ford also sells the 65 series in a 750 and 850 amp version.

Aftermarket battery in the truck before they changed it?

 

It was a Gold Series Autocraft battery.

Update: I think i have finally fixed the issues. The stronger battery made it start more often, but it still would only start 1 out of 3 tries. Last night I replaced the Fuel Pump Relay, and for the last 5 starts, it has started on the first try.............and today it was 2 degrees when I did it. It appears it was the Relay all along, I am sure my battery took a beating with me using it up trying to get the engine to start. Bottom line, if you ever suspect a Fuel Pump issue, spend the $9.99 and replace the fuel pump relay first.