Snail's-pace plotting and consistent overwriting mark this second outing for a singularly uninteresting Washington, D.C., private eye named John Rankin, who made his debut last year in Grady's Runner in the Street. John Rankin is described as ""child of the '6Os, hero for the '80s, and the hottest embodiment of cool in years,"" but judging from his plodding performance here it seems more likely he was once voted Most Likely To Be Fitted With Cement Overshoes, and is simply seeking to fulfill that early promise. As the novel opens, the handsome gumshoe is lunching in a ferny Washington restaurant with a beautiful mystery woman who calls herself Cora McGregor but comes on like Faye Dunaway in The Thomas Crowne Affair, all chic, slim arrogance and wide sunglasses. She hires the smitten Rankin to find out if the police are still actively pursuing the murderer of Parviz Naderi, a shady Iranian maitre d' who was killed in 1977. Naderi is a clumsy and obvious red herring, but Rankin's boring search for information does give Grady the chance to show off his superficial, street-map kind of knowledge of the town, and to pontificate: ""Washington is a city of myths,"" Rankin somberly intones. The real story is that Cora is actually Barbara ""Bobbi"" Sloan, the unhappy wife of sadistic Washington wheeler-dealer J. Emmett Sloan, who killed Naderi when the man double-crossed him and is threatening to do the same to Bobbi if she leaves him--besides which, he won't support her widowed mother anymore. Unable to handle the pressure, Bobbi melodramatically commits suicide, but not before she and Rankin have the kind of love affair which can leave readers wincing for days: ""She smiled and something in me exploded. 'You're a fever in my blood, Bobbi!' . . . As we rocked together she cried my name and words I'd hear often, never enough: 'Fill me, John! Fill me!!!'"" All this clunky nonsense from the writer who 11 years ago gave us the estimable Six Days of the Condor.