so on the way home today from school when i got on the freeway it felt like i was towing. It was really sluggish feeling and when i do freeway i normaly average 17.5. but tonight in cruise control just to see if i was right i was sitting at like 12.4 on the programmer.

Any suggestions

 

Running the a/c? Hot out? Fan clutch engaged? Bad gas? Run seafoam threw it....

 

Running ac= no
hot out=yes
fun clutch engaged=?
bad gas= 89 octane
seafoam= through gas tank but at 45 the vehicle still does the normal 18-20

 

anyone knows whats up was doing again today for a while and all of a sudden it settled down till i gave it gas to get up the ramp on the freeway and it started doing it again.

Seems like after i give it full throttle it runs like that till i turn vehicle off

 

What motor? 2X4 or 4X4? Auto or manual tranny? If you give enough information you may get an educated response. What have you done to it lately? On the little bit of info you give it sounds like all cylinders are not firing.

 

its a 2001 f150 xlt supercrew with a 5.4 auto.

In last 3 months
plugs changed
oil changed


It only does though after i give it full throttle. If i come to a complete stop it seems to be good again to till i floor it then it starts doing it.

 

fuel filter???

 

done 35000 miles ago

 

May be your MAF sensor. Try cleaning it with some MAF spray cleaner and while your at it try cleaning the throttle body. You did not give your mileage but it could also be a COP going out.

 

im sitting at 118000 on the speedometer but realy at 126k