2000 f150, cranks but will not start, interior lights flashing....?

First: no offense...but cranks presumes starts. Might I suggest you state that your vehicle: engine turns over but won't start? Again, no offense.

did you find out what was wrong with your truck?

Problem,cool weather set in and not using ford f150 too much. I try to start but only cranks but wont start.Relpaced the fuel relay but nothing?

what year is your truck and engine size?

Stevie, my truck F150 4.2 L 6-cyl.

Sorry, it is a 2001.

if the fuel pump fuse is not blown or the fuel pump inertia switch is not tripped from hitting a pot hole or curb or accident,then the fuel pump should come on for 2 seconds in the tank and then it turns off.it primes(humms)for 2 seconds every time the key is turned to on,not start..CAN YOU HEAR IT COME ON AND GO OFF?

Funny thing is I tried it this morning and I heard the fuel pump few times but tried later and nothing.I was also told also that the ant-theft can also cut off your pump if it is defective. Very confusing now.

if the Theft light is not staying on or flashing,then it's not the PATS theft problem.my 2000 F150 took one year for the fuel pump to completely go out.when you turn key to on,the theft light comes on solid,and then goes out in 3 seconds.the factory fuel pump ,i just changed last year.it lasted 15 years and 303,000 miles.it had the date stamped on the pump,8/24/2000.did your truck start when you could hear the fuel pump come on this morning?

No, I just turned the key and heard for the sound . Tried again this morning and no sound. My truck doesn't have many miles( only 89,000 for 2001). Was using it constantly here in town with only few times out of town. My work was only 10 min. away. But retired now and basically would just run the engine and minor errands. Looks like soon as not used much this occurred.

you are going to need some hands on help i believe? fuel pump fuse powers the relay,then relay to inertia switch(fuel pump cut off safety switch),then inertia switch to fuel pump connector.you need a volt meter and a helper.you will only see power for a split second when testing.if you have power to the fuel pump connector and it's not corroded up or loose and the pump is not coming on,then take the bed off of the truck and replace the fuel pump,no need to replace the sender if your gas gauge reads correctly, only the pump motor! you most likely have a bad spot in the pump motor.there are 6 TORX PLUS>TP50 screws holding the bed on(spray PB Blaster under neath on screws before trying to remove them) with an 18 inch 1/2 inch drive breaker bar reduced to 3/8 ,get under the drivers side rear bumper and unplug the tail/brake/turn lights(one connector),unplug the 2 tag lights,remove vent tube from bottom of bed,remove 3 screws inside the gas cap filler,push neck thru to inside of bed,remove the tailgate,get 4 strong men,one on each corner,pick bed up OVER the tires and bumper(don't let it tilt towards the cab),set it on saw horses or just the ground.i have a short bed on mine,bout 500 pounds! this only works on reg cab,and ext cab,will not work on crew cab,because the fuel pump is under the back seat on the crew cab,tank has to be dropped.

my 2000 F150 extended cab bed off pics....

my 2000 F150 extended cab

my ext cab 2000F150

bed off 2000 F150 ext cab