I have a 02 F150 W/4.6lt 2wd w/156k miiles on it: Just 2weeks ago I replaced my fuel pump with all of the sending unit. I refiled tank everything running fine and went on a small road trip but after is got to 1/4 of a tank it started to act like it was vapor locking, so I found gas station and filled tank had no more issues that day, got home and than again after it got down to a 1/4 of a tank it started up again and this it power down waited for 15 minutes and releved pressure in the tank and it started back up again got to a gas sation and filled it back up. NEED HELP Roman

 

How much gas are you putting in the tank every time? Also, how big is the tank? If the tank is (for discussion only) 20 gallons and you put in 18 gallons, the sending unit arm is stuck on top of a baffle and reading incorrectly.

 

Checked my receipts and we only put in 14 gal to fill it up, Also I did replace the fuel filter, one more thing it only act up when it get hot, we have been in the upper 90 deg range Roman

 

it is possible the Fuel Tank Pressure sensor is not operating properly. This can allow pressures to build up in the tank and will cause the vehicle to run lean.