Trouble starting in park.

Somewhere in the linkage system, I believe you will find a round bar with a flat side that runs through a sort of clamp that has a bolt that holds the flat side of the rod in place. Loosen the bolt so the rod can slide in the clamp. Put the gearshift in park. Actuate the shift lever on the trans so that it is solidly in the park position (you can feel it) and then tighten the bolt in the clamp to hold the rod in that position. Test the results.