  Since four-fermion operators in strongly coupled $QED$ are nonperturbatively
renormalizable, we analyze here the phase diagram and critical behaviour of the
Gauged Nambu-Jona Lasinio model. Our mean field approximation relates the
critical exponents along the continuous phase transition line with the mass
dependence of the chiral condensate in the Coulomb phase of standard noncompact
$QED$. The numerical results for noncompact $QED$ strongly suggest non mean
field exponents along the critical line.
