z28 NyC

Ok this has been happening to me on and off every few months or soo, I get a no start, usually out of nowhere or after just driving the car, I plug in my snap-on spark tester in series with the # 1 plug (throws a flash of light every time spark is fired/handy little tool), I crank...no spark, crank some more...no spark, crank some more (...and heres the kicker) and as soon as I LET GO of the key (and only when the key is let go of after cranking) I get a spark and the car starts, this happenes maybe 2 out of ten times of cranking. Now usually when I get this problem I take out the coil, pull the cap/rotor, remove the module and inspect everything, I clean everything up a little, put everything back together and it usually starts right up but thats not working anymore, I believe the problem to be the pickup coil and/or the ignition module....what do you guys think....?

stock 305-resealed
quadrajet 4bbl-no choke non-computer controlled
msd cap/rotor-in good condition
msd replacment hei in cap coil-fairly new
stock 4 **** module
pick up coil-never changed

voodoochikin04

heres an idea, im not 100% sure so anyways. it could possibly be that when you turn your key all the way, somtimes power isnt getting to the coil, via your ignition switch, but on the backstroke it makes contact, therefore causing a spark when releasing the key.. just an idea.. possibly change the ignition? or check wiring behind the ignition switch