Temporarily bypass the fuel cut off and take a short ride to check that. It will either need disconnected or jumpered, I'm not sure wich.

That would be my second check, as it's among the easiest.

Grounds can only be cleaned and if needed re-tightened. This would be a good time to add some extra ground cables to the engine for a little improvement on performance. Or if they need replaced just go bigger. Subwoofer amp cable is a cheap and reliable cable, and is guaranteed to handle the engine compartment.

ECU is the last thing I would think of, mostly because It would not likely only happen in corners if that were it, plus you really don't want it to be something that expensive. I think some shops and parts stores can check it for free though.

Best of luck, Hope you get it fixed.