89 chevy r2500 runs and dies

My truck has recently decided to run for about 20 sec then dies , I have replaced cap rotor ignition module coiland seems to be getting fuel as it should, any thoughts

Might be a problem with the pick-up coil in the distributor.

https://www.rockauto.com/catalog/moreinfo.php?pk=4588572&cc=1060030&jnid=478&jpid=0

Tester