I need some help!...Please!

I've been dealing with this since the first of the year with no resolutions.

The check light and flashing arrow came on, the car goes into limp mode, and code P0705 was retreived. While working out of town, I had an Import Shop look at the car. They replaced the Gear Sensor switch. The check light and flashing arrow came back on the way home.

Had another (local) shop check the codes and they pulled a P0470 at 332, so they replaced the lock up (or out?) solenoid, serviced the transmission, and reset the computer.

The light comes back on again with a code of P0705 and they suggest I take it to the shop that installed the Gear sensor switch. I was able to do that, but after they checked things, told me I needed to take the car to the dealer....I live 100 miles from the nearest dealer, but I do it anyway because I'm running out of people to service my car.

At the dealer, they checked/test drove the car and told me everything looks really good. They suggested someone failed to erase the previous codes. The codes they got were "EFI666 (not certain what that stands for) at 332, 311 and 313. They erased those codes and warned me if the light comes back on I have serious trouble.

the lights came back on....ugh!

Can someone give me an idea of what might be going on? THANK YOU!!!