Alright so im brand new to this forum just seeing if anyone can help me solve my problem. 87 z28 camaro with the 305tpi,car had been starting all day and when i went to start her up to leave my house it turned over but no spark.did some tests to some of the ignition components,ended up replacing the icm and the coil and still no spark.so i heard from someone to try unplugging the aftermarket tachometer wire from my coil,so i did and it started right up! let her run shut her down and started up fine again.tried to start again hours later and once again no spark. I have no idea what the hell is wrong,has anybody else had similar problems or have any ideas to try,all response is greatly appreciated!!!