Chrysler Repair: 96 Chrysler Concorde: codes 134/171/300, exhaust gas recirculation valve, side exhaust manifold

Question
My 96 Concorde starts up and then it shuts off while I am driving or at a light or at a stop sign and I have to put in park to start again.  I took it to Autozone and got a diagnostic reading and the codes were "P0171, P0134 & P0300".  I changed the spark plugs already and the problem still exists and I know that there is an exhaust leak due to the previous owner cutting off the catalytic converter

Answer
Hi Anthony,
The 134 and 171 both point at the oxygen sensor on the right side exhaust manifold not working. If the problem manifests itself only after the engine warms up, then that is probably the explanation. Otherwise, in the absence of other specific codes I would suggest that you check the exhaust gas recirculation valve (egr) to make sure that its stem is moving freely and that the internal spring-action closes the valve to a dead stop by means of a screwdriver inserted in the slot of the stem. You can spray some WD-40 on the stem where it enters the body of the valve to free-up the action. The 300 code just says you have multiple cylinder misfire which could be due to the oxygen sensor or the egr valve sticking slightly ajar when at idle. Otherwise there are many things that one could check. So I'd start first by changing the sensor and checking the egr.
Roland