  In this article, we construct countably many mutually non-isotopic
diffeomorphisms of some closed non simply-connected 4-manifolds that are
homotopic to but not isotopic to the identity, by surgery along
$\Theta$-graphs. As corollaries of this, we obtain some new results on
codimension 1 embeddings and pseudo-isotopies of 4-manifolds. In the proof of
the non-triviality of the diffeomorphisms, we utilize a twisted analogue of
Kontsevich's characteristic class for smooth bundles, which is obtained by
extending a higher dimensional analogue of March\'{e}--Lescop's "equivariant
triple intersection" in configuration spaces of 3-manifolds to allow Lie
algebraic local coefficient system.
