I find that with my 2tgeu (it has twin carburators) many of my idle problems were due to the distributor. I found that my points were worn and after hard driving it caused a poor idle. The rest of my problems were with the twin carburettors, they required a tune. As you have EFI it does not realy apply to you. As oldcorollas mentioned I would check all the vacuum piping (Around distributor, manifold).