Ticking noise while driving?

Hi audi coupe 94 2.0 16v ace , while im driving i can hear a ticking noise coming from somewer think from engine thats my guess , the ticking noise gets louder on aceleration, if im parked and rev the car i cant hear anything only when i drive , noise is more noticeable when driving past other cars.

ticking is usually tappets with these cars, but if it is not dependant on revs, more noise with more throttle, then my guess is blowing exhaust manifold gasket, or cracked manifold?