Hi jwill49. Welcome to the forum. One real common cause of these symptoms was the original spark plug wires, but they should have acted up a long time ago, and it only applies to the 3.3L engine. A partially plugged catalytic converter can cause this too, but it is not typical of an oxygen sensor. Usually when the converter is plugged, the engine will idle uncommonly smoothly and you will hear more of a hiss from the tail pipe instead of the normal "thump thump".
A cracked core for the crankshaft position sensor will generate extra or incorrect pulses causing cylinders to fire at the wrong time. This can be hard to find without a diagnostic scope. The core doesn't usually crack on its own. It occurs from inproper installation procedures. New ones will have a thin plastic rib or a paper spacer on the end to set the correct air gap. The rib will partially wear away or the paper spacer will slide off when the engine is started. When reinstalling a used sensor, any remaining rib must be sliced off, then a new paper spacer installed to set the gap. Spacers are available from the dealer's parts department.
The MAP sensor can cause this when it sends incorrect values to the Engine Computer, but eventually it will fail completely and the Check Engine light will turn on. This sensor doesn't take very long to fail completely; rarely more than a few days.
Caradiodoc
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Saturday, April 17th, 2010 AT 2:05 PM
