Engines of 4.3 L V6, 5.0L, 5.7L, and 7.4L V8 manufactured in 2014 and before have their MAP sensors positioned at the right side of the intake manifold while those of 4.8L, 5.3L, and 6.0L V8s are located at the back of the intake manifold. The first step is to disconnect negative battery terminal cable which is followed by removal of engine cover and then unclipping the electrical connectors from the MAP sensor finally it can be pried out with care using two small screwdrivers by sliding them between both sides of this sensor as well as mounting bracket to make it free enough for easy removal. If you see that your MAP sensor O-ring has cracks or wear marks on it, take it out and examine it carefully to ascertain whether these were caused by damage during its lifespan or not.