my car has a bad mis, poor power, and afew cylinders getting spark but not firing. Bad Ideal ect... been making me nuts! After looking more into code 42 I see it could possible be a bad ecm or ign. modual. Dumb question.. does that mean I need to replace the computer or just the Ign. mod under the car on the distributor????? thanks!

 

I had a 83 crossfire motor do this yes I know way different year .... 42 was being triggered by a bad magnetic pickup coil in the distributor ..... symptoms the car had were

Bad fuel odor
felt like it was running on 6 to 7 cylinders
used an ungodly amount of fuel as well

this code was in reference to est (electronic spark timing) circuit. I tried new ecm, ignition module, esc module, knock sensor, coil ..... Hope that helps a little. I know your car is alot newer and all but it works the same as my old CFI electronics

Good luck