my 2011 F 150 Starts right up but amp gauge reads exremely low but when driving it very slowly comes up, No check engine light comes on.

you need a multi tester , you need at least 12.5 V from the batt. at rest , and 14.5 when once you start it see if the dash matches the test , , the batts not going dead (yet) , did the batt. light come on the dash ? There's a gauge you can plug into your cig. lighter to get a second opinion on voltage . Or you could probably do the test from there it just wouldn't account for any voltage drops . Let us know what happens .