the acceleration won't be too fast, these are pretty slow trucks. and for the intercooler, if you look on the underside of the hood, there is ducting that gives it airflow from the grille and routes the airflow through the hood to the top of the intercooler. there is also a small fan on the underside of the intercooler to cool it. the 2.8 4M40 engine got the hood scoop which came out later in 1993.

but timing belts/ fluids are a good place to start.