I believe it has electrick timing and it adjusts at the cap. Not sure if timing light is useful here. How can this be tested and adjusted? correctly

 

There is not timing adjustment on your truck. Turning the distributor adjusts injector timing as the dist. is the cam sensor. In order to adjust it you need a scan tool that displays data. You need to look at the data and adjust it to 0 +or- 2. If it is not correct the check engine light will come on with a code for cam crank correlation (p1345 if I remember correctly)