My situation :

I'm runing a bone stock 305 (roller block) stock tpi setup, with stock cam , stock computer controlled hei distributor , stock ECM tune , initial timing set 6ºBTDC , new accel 8mm spark plug wires , new accel spark plugs (i've checked the gap).

(click on p/n for summit product page)

I've replaced my stock coil and my stock ignition module , with coil Petronix PNX-D3000 and matching module Petronix PNX-D2001 , and i feel a little "pooop" every 10 or 15 seconds when i'm idling , i've checked for vacuum leaks , no leaks found.
When i feel that "pop" sound , i notice a retard on the timing ( 2º or 3º for a second) , sounds like a problem with dwell control of the module.

Any ideas ?

Thanks.