Intermittent Running Problems

Hi hope somebody can help me asap with a ford focus ghia auto 2005.

About two weeks ago i called out the AA as my car wouldn't start. AA said the immobiliser light was flashing so it needed taking to a garage, i agreed to have it towed to evans halshaw. Two days later they fixed the problem and said it needed a new connector on the immobiliser. The same night whilst on the motorway all the lights came on the dashboard and the car went into limp mode and lost all power to the dials.

Stopped at the services and turned the ignition off and retried to turn the engine back over but the immobiliser was flashing again. I waited ten minutes and the car turned over

Rang evans halshaw back up to complain and they agreed to take the car back in. So i rejoined the motorway and within five minutes the car once again whent into limp mode and lost power to the dials. When slowing for traffic the car sprung back to life and would again let me build up some speed but the engine light was on constantly.

Managed to get back to evans halshaw and left the car with them. A week later i call up for an update and to my disbelief they told me they haven't had time to look at it yet. They said they will get someone to look at it that same day. A few hours later i get a phone call saying they have had it on the diagnostic machine and cant find anything wrong with it.

So i agreed to let it go out on a test drive. A day later they are still telling me they cant find anything wrong with it. As of today its still in the garage waiting to go out on another test drive.

Any help with what might be causing it would be helpful, thanks

When the car wont start the immobiliser light is flashing and a engine systems fault is displayed on the dashboard computer withe the message transmission fault.

When it goes into limp mode it also displays the engine systems fault message and all the lights come on the dash and looses power to the dials. And wont let me go over 30-40mph