I have a 2006 f150 with 5.4 3v in it and I have problems reguarding engine stalling after its warm and driving for about a half hour, when I put it in nuetral it starts back up and then dies again and will eventually not start at all, I’ve already replaced the fuel pump driver module, throttle position sensor and mass airflow sensor. My truck also idles at 500 rpms when warm, ive read to replace the idle air control valve but my truck controls idle air through the pcm not a separate valve. I just want to get this problem solved because as of now I can’t drive my truck continuously for over 30 minutes before it stalls on me.

 

Have you cleaned the Throttle body?

 

yes and I’m starting to think it’s a clogged fuel filter or fuel pump relay

 

why would a clogged fuel filter only clog when warmed up ? and codes ? mileage ?

 

how old are plugs?

 

I am having the same issue. My plugs were replaced 20k ago, Fuel filer was changed when I did my timing 1,600 ago. Cleaned the TB the Friday before last and it was filthy. At operating temp the engine will drop to around 530 RPM's at idle in drive. Lower in Reverse, but 800 in neutral.

 

I’m thinking fuel filter because it has a rough idle and when I come to a stop light it idles perfect for about 5-10 seconds and then starts getting rough as if it used up the fuel at a higher pressure all the way back to the fuel filter. The mileage on the truck is 200,000 and the previous owner may not have changed the fuel filter.

 

just changed them recently