Why are you so convinced your DME is the issue?? They rarely have issues and rarely need to be reflashed.
These cars are 100% predictable if you read and pay attention.
Just be glad you did not buy an Audi or Mercedes!
Suggest you start over with what you problem is and what has been done to the car so far.
Suggest you read the fist 2 links below in my signature.
If you do no want to do maintenance, suggest you lease your cars!