My mechanic brother and I am racking our brains over this one. I have a 1995 Buick Century with 149,000 miles that will occasional and randomly idle rough when started warm. Also, on several occasions it will idle so rough it kills the engine and I’m unable to start the engine until the thermostat reads completely cold. I’ve taken it to 2 separate mechanics who both are unable to pull any error codes (even after the engine has died) and are unable to duplicate the problem. When it does idle rough most of the time I can rev the engine, put it in gear and drive it for a few minutes and the problem disappears. Other times I try to put it into gear and it kills, I put it into park and try to restart the engine and the engine will start for a brief second and then die and will die faster each time I restart until the engine doesn’t turn over at all. Then once the thermostat reaches ‘C’ it starts up like there was no problem at all.
Here is a list of recent pertinent repairs: Replaced Battery 12/2/11 Replaced plugs and wires 4/11/12 Throttle Body Gasket and Fuel Filter Replaced 3/18/13 PCV Hose replaced 2/19/14 (last mechanic's guess on the problem)
I don’t notice any signs of a rich fuel mixture or abnormal exhaust (there was a discussion with a Buick with no start that had this). Does anyone have any ideas?
Thanks for the help!