1986 Chrysler Lebaron Turbo Convertible has acceleration problems.

Just inherited this car (28K miles) which has been driven very little over the last 12 months. Although warmed up substantially, when I drove car on to freeway, it would hardly accelerate such that I couldn't even keep up with traffic.  As I continued to press on accelerator, it eventually started to speed up to the desired limit.  Problem seems to be purely acceleration or lack thereof.  I became so concerned with what seemed to be a stalling out of the engine that I thought I was going to have to drive onto the side of the highway to avoid traffic.  Eventually got car to my home and thought by driving some 40 miles at highway speeds that the lack of acceleration would have been corrected.  Problem still persists.  Help.