Audi 100 C3 2.5 TDI – All at once engine off

Hello! I have quite a problem with my 2.5 TDI. Unfortunately I don’t find much information, the engine is too rare or never causes problems haha. Well to my problem I was on the highway 2 weeks ago, the car had NEVER made problems before. Everything went round until the speed fell at once to 0. Engine turned off, turned on the warning light and called the ACL, because the car did not want to start. I tried twice. Once he went on immediately, but jumped d he speed was high – on the speedometer the speed remained at 0. After that I tried again, but this time it took about 15 seconds until the car was on again. And the engine ran very rough and low. But the speed was still at 0. Last Friday I tried my luck again. The car started immediately, and died immediately. Second time it took longer, and the speed jumped to an estimated 2500, but the speedometer still shows 0. 3 seconds and he went again Over and over again. Trying to push the accelerator a bit, and the car then ran up to a moment, the speed went extremely high so I feared a Runaway diesel and pulled the key. The car has 140,000KM. Check booklet, always oil change, filter change, everything. I am unfortunately student and have inherited the car because it was already my dream car. Am now just destroyed and nobody can help. Does anyone have any more idea here? The car is in Topzusta and that he just goes out and never starts again I just don’t want to thank you in advance! MFG