I'm in the same boat with milage and a fast idle. I haven't been on here for awhile, getting Christmas $$$ overwith and avoiding getting wrtenching fever on thewire...
I picked up a new 195 T stat today. And the wrong temp. T-stat can make a big difference. Especially when it comes to passing emmissions test.
I have a H2O sensor coming Wed.
If that doesn't do it ,,,it's on to the ICS...

dave h.
'89 Raider V6 5spd;Aisin Hubs;; Gen2 LS: frt. brakes, rear coils;U.C.arms;R.trailing arms;idler arm; rear LSD axle w.disc brakes ;2 battery system for Dog's fan; relocated ECU; custom bumpers;J.Baker receiver;Conferr roofrack; t-bar crank.