Stalling at idle?
In the morning, sometimes when I start it up for the first time, it will turn over fine and idle smooth for about half a split second, then the RPMs will drop to about 300-200 rpm and run rough as hell, almost stall, then after 1-2 seconds catch again and rev up to around 1200-1300 for a few seconds, then drop down to a normal 800.
Bizzare, eh? It's stumped several mechanics. It's happened for the past 3 or 4 months, and I've noticed it'll do it a lot in cold weather, so I'm thinking maybe the 02 sensor(s) aren't heating like they should, so when the truck starts they start sending false readings which chokes up the engine, untill the exhaust warms them up, when they start working right. Other than that, I don't know what it COULD be, the entire ignition system is ok, air intake is ok, filters are all new, fuel system tested ok, and the starter is fine.
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