In the AD-AS model, suppose an economy is in long-run equilibrium. Then there is a demand shock; AD shifts right. The self-adjustment mechanism will bring the economy back to potential output.

Will the self-adjustment mechanism cause an inflationary spiral?

As a result of the aggregate increase in demand, the market will be willing to pay a higher price at each quantity along the demand curve. This will entice suppliers to produce more, in an attempt to capitalize on the higher sales prices. However, in ramping up production, the supply curve will shift outward to the right. This will put downward pressure on prices and reduce the equilibrium price back toward its original position. This is not an inflationary effect. The effect is deflationary.