My 2001 F150 5.4 starts hard after sitting for an hour or 2. It starts fine in the morning at 5 degrees. But after I shut it off and let it sit for awhile I have to crank it over longer than usual. It will start and then kill. Then I crank it again for maybe 5 seconds and it starts. The engine idles normal, no reving up or sputtering. I know it needs plugs, 96K on these. It just started acting this way when we had a few warm days in the 40's. Any idea's? I was hoping I could wait til warmer weather before I change the plugs.

 

It may be the fuel pump getting weak.I was told that the elect pumps were good till about 50k are so,then needed to be changed out.Turn the key on and wait a min for it too pressure up,then try it.

 

Not sure why it would start in cold weather fine but hard after its warmed up but if the fuel pressure regulator is on the engine you can check it. Run the engine to warm it up then shut it off. Pull the vacuum line off the regulator which I think is next to the throttle body on these. If the vacuum line has fuel in the end of it or is even just wet with fuel then the regulator is bad and needs to be replaced. This will cause a vehicle to start hard after sitting a while (as little as 1 hr) due to the fuel pressure bleeding off just like a bad fuel pump. I think that if this were the case though that the engine would start hard in the morning too. Good luck.