Ford Repair: Tire Pressure F 150, tire pressure guage, optical illusion

Question
I have a 2003 F-150.  I plan to do some heavy hauling on the highway so I checked the tire pressure.  Front left looked low, so I filled it.  Didn't take much air.  Yet even after filled to 30 PSI it still looks low.  Thought the electronic guage I was using was wrong but a mechanical tire pressure guage said the same.  Any ideas?  Thanks, Ed.

Answer
there are a couple possibilities. first of all, you should set your front tires to atleast 35 psi. if your gonna tow depending on the load rating of the rear tires, set them to atleast 45 psi. as far as them looking low, it's possible your front end has a camber or toe alignment concern so it's an optical illusion. may want to take it to a shop and have alignment checked