4k won't run

[Kenneth Folkman Jr.]

My brother's '86 4kcsq won't run.  It used to have problems starting, but it
would eventually run.  It will start right away, but only run for a few
seconds, then die.  This will happen a couple times, then it won't start at
all.  Then if we wait about a minute, then it will start running and die.
This process will repeat itself until the battery dies.  Another thing is if
the accelerator pedal is pressed while the engine is running it will
immediately die.  We don't have a Bentley manual, so any help would be
appreciated.

Kenneth