Chevrolet Repair: 1987 chevy silverado 5.7 throttle body injection, vacum leaks, chevy silverado

Question
i have a 87 chevy with a new 5.7 ( only  about 20k miles)  seems  to run ok...but  when i 1st start it in the morning  it runs really rough ...and after  its  warmed up its better  except  it seems to cut out when sitting  at a lite...almost  seems like someone jogs in ignition key...it  doesnt stall...but  a few  times  i really thought i was  bumped  from  behind?   plugs wires cap  and the  common items  are all new....where  do i start?  i  dont  want  to  replace  everything,   thanks  joe

Answer
Hi Joe.... it could be one of several things....check for vacum leaks, cracked or collasping hoses, check around the throttle body...check ign module...check coil...check for bad fuel pump or fuel pump relay...check grounds, check all connections for corrosion, bent connectors...check with a scan tool for any codes...check any power wires that may be frayed and touching ground... check main power wire at the starter...i know it isn't much but i hope i pointed you in the right direction....