89 f150 5.0 I had 3/4 tank of fuel in front and rear tanks I use front tank then rear I noticed on front tank driving it would stall I would switch to rear and it would start running again I would switch right back to front tank and it would run ok then maybe next day it would do it again. Then I noticed front tank fuel gauge did not seem to be going down I checked rear tank and was almost empty. even though gauge read correct it was drawing from rear tank and set on front. I no the low presure pumps in tank is what switches the mech dual function switch and if one goes bad it wont switch and the high pressure pump will draw from other tank. But I can turn my key with selector on either tank and can hear pump kick on. Could it be in the selector....