Truck is a Ram 1500 4x4 with the 5.2 liter 318 motor.
So I've had a CEL for years that was related to the O2 sensor. It didn't affect the function of the truck, so I just left it. At the start of this winter, I drove it a bit and parked it, running, to unload. The truck died when I was inside. I started it again and parked it. Since then, I've had lots of problems with it dieing at idle, either at a stop or if I let it run long enough in the driveway. I replaced the Air Idle Control Valve (AIC), removed and cleaned the throttle body, replaced the PCV valve, the breather element and the air cleaner. There is no EGR on this truck. Last year, maybe the year before, I replaced spark plugs, ignition coil, spark plug wires, battery and alternator. I've had the fuel pump replaced 3 times now, most recently last summer. I also have checked for vacuum leaks using both carb/choke cleaner and an open propane tank and found no leaks. I replaced both O2 sensors, pulled the battery to clear the CEl and have not had a CEL since. I have checked with a scanner and there are no codes, no pending coded, the O2 voltage is fluctuating like it should, almost towards the Rich end of the scale. The TPS is showing throttle changes and the idle RPM is around 730. I've used an infrared thermal scanner to check the exhaust headers and two are much cooler than the rest, leading to a thought it might be running rich on those cylinders, or there is incomplete combustion. Since I've pulled the batter, I've driven over 50 miles and have tried the highway speed, off the gas/no brake for 7 seconds for no luck. The only think I think I can try next is to replace the TPS, or to just sell the darn thing. Any thoughts? I tried to put a ton of info in this post since I've done so much to it.
Monday, February 6th, 2012 AT 8:52 PM