Ok...well ive noticed it a couple time lately doesnt happen all the time just when idling back in reverse car will completly shut off no stumbling which is making me think ignition related.

Recently Replaced:

MSD 8.5 mm superconductors
Accel High Performance Dist Cap
AC Delco Plugs

Fuel Filter
Fuel Pump

Timing was advanced just a lillte bit

Any suggestions???

Also I have a surging problem with the defrost on maybe vaccum leak??

 

Check the primary ignition wiring, ground straps, and plugged connections at the distributor, ESC, coil, and fusible links. The opposite torque-up of the engine in its mounts caused by moving in reverse could be straining a weak connection.