Audi A3 1.8t - Audi A3 non starter?. - apd1979

My 1998 A3 1.8t has an intermitent starting issue. Most days it starts and runs fine then all of a sudden it just wont start. Ther engine cranks over but wont fire. Sometimes if left for several hours it will start without fault and run/start fine until the next time it happens?. Ive read about fuel pump relays going so tried another relay, no joy so guess its not the relay. Previous owner recently had a new cam sensor hoping to solve the problem. No joy. Fuel pump primes fine every time ignition is turned on so guess its not that?. A guy told me last night he reckoned this is classic crank sensor failure?. Anyone got any ideas?. Its got an agu engine with 112k and full history. Thanks.

Audi A3 1.8t - Audi A3 non starter?. - elekie&a/c doctor

Could be a crank sensor.Any diagnostic codes stored?

Audi A3 1.8t - Audi A3 non starter?. - apd1979

It has been on a diagnostic by previous owners mechanic but showed nothing?. They replaced the camshaft sensor but still had the problem. Fuel pump relay looks to be new and tried a known to be working relay with no joy!. Ive heard the crank sensor is common with these symptoms?.