Ok, so I have a 93 S10 Blazer. 4.3 CPI. After dealing with some hard start issues, it finally just went to no start at all. No spark. Troubleshooting led me to either the coil or ignition control module. Replaced both and now I get rough idle. (Lopes up and down) with the code 42. Any ideas? It'll start to rin better as it warms up, but if you shut it off and restart, its back to the same issue.