diesel purge and valve adjustment
With that said, lets think about things, This car is 28 years old and in all likelyhood could benefit from cleaning the injectors. Diesel purge is easier than removing the injectors and having them rebuilt. It will clean them, but if the injectors are weak or off on "pop" pressure, that will not be taken care of with Diesel Purge.
Concerning the valve adjustment, the valves should be adjusted annually or every 25,000 miles. This is an overhead cam engine and the gap between the cam and follower will decrease as things wear. If it decreaser sufficiently then hard starting and low power will be the result and if not taken care of eventually a burned valve will occur. HTH



