190 2.3-16 hard to start and keep idlng during hot start.

My 1986 2.3-16 has a slight problem. During the summer months, after sitting for a while after running the car is very difficult to start and keep idling. It wont idle at all and when it does, it idles at 500 rpm. This will continue for maybe 15 minutes after starting. What is wrong with it? The fuel injectors have been replaced and the fuel filter is quite new. Is it the fuel accumulator that is causing this hard start? If you need to know, it is the original accumulator that came with the car since 1986. The fuel pump is also the original unit. Any assistance will be appreciated. Joe