First there is three different engines for that model truck. What is the eighth digit of the vin number. Second what leads you to believe you need to replace both knock sensors. Yes it has a front and rear knocksensor. What is even worst, they are under the intake manifold. That's assumming it is a 6.0 V-8. It sure is a lot of work to be guessing at it. What are the trouble code/codes. Post that and I think I can help you further.