this is the code im getting on my lt1. 9/10 times it will not crank but when it does, it will run horribly and then die after a few seconds. i know it has to deal with the spark but im not sure as to were to begin. i did have the icm tested and it passed. what should my next step be in solving this?

 

Found some good info about the issue here:
GM Scanner found code 42 EST How do you fix it


It's all about the wiring. Check your grounds and ICM wires for shorts.

 

well i hope i got this problem fixed. i put new greese on the icm and checked some wires. i couldnt really find anything wrong with them except the wires to the compressor were touching the headers. they dont appear to be burnt but idk the condition of the wires (idk if the ac works right now as to it needs to be recharged). but now it took me abit to get it started and i would have to pump the gas to get it started it and its throwing a new code. 36 high resolution pulse failure. from what i found this is due to opti failure? or the pigtail off the opti?