Well got the 390 in this weekend, but now it idles rough and wants to die when I come up to stops. Put a new iac in cuz it came apart when I tried cleaning it. Runs great when I bring theR's up, but wants to cut out when I let off and at idle it sounds like its missingbut not getting any codes. I installed a new Hughes big gulp throttle body on it, is it possible that the idle screw behind the Lil plug isn't adjusted correctly?
another issues the second Gen computers have is after being disconnected from a battery for a period of unknown time, they get goofy... in the exact same way your describing that running problem. so answer this... how long have you ran it like that? I ended up running mine for a half an hour around town, playing with the gas and brake to keep my rpms up when I had to stop at lights or signs. after a while... it's almost as if the computer relearned itself and remembered how to run again. goofy I know, but I've experienced it know both of my second gens, once when I replaced a trany and once when my truck sat for my 6 month deployment
well I looked at the screw between the new throttle body and the one I had on there and they appear to be adjusted the same. ive put about 20 miles on it already and it still does it. I even tried adjusting the tps sensor and checked all the wire connections again