check engine light on reverse goes in hard

Diagnostic testing is required to find out what is happening. Sounds like there will be set codes that can be inspected with a good diagnostic tool able to not only interface with the engine's processor but that can also inspect the operation of individual components. Hopefully you'll be able to see what area needs attention then troubleshoot from there. Here are some shops near you that can help: https://repairpal.com/repair-shops