Audi 80 1.6 petrol starting/running problems

[jbfw]

My Audi 80 starts from cold, runs a short time then cuts out . When I try to start it again it just turns over but not firing up, then when you let the key go back it attempts to start but does not.
It won't start up again until next day & the same happens. I have changed both temperature sensors on the hose housing - blue square one with 2 pins & round grey one with 3 pins.

Any help would be appreciated. Thanks

[zollaf]

hi & welcome. what year, carb or injection?. when you say you let go of the key, it then turns over???.

[jbfw]

Hi, car is 1995 and injection.
When I turn the key from turning the engine over postition back to ingition on position it tries to start up but doesn't