1999 concorde codes p0355 and p1391, The symptoms are: runs fine until the engine reaches operating temperature and then the engine may misfire randomly. Sometimes the engine will miss quite a bit and then sometimes the engine won't. This miss seems to be a "hard" miss when it happens. Every once in a while the engine will die at idle speed but will immediately start back up and then may not die again. I was told that it was probably the ignition coil on the #5 cylinder which is the cylinder described in the code p0355. I was wondering why the code p1391 would show up but a mechanic told me that the coil misfire could also cause the code p1391 to show up. Help would be much appreciated.

I suspect that your mechanic is correct, but if the crank sensor is dropping out, which is very common on Chrys. products, that can cause your symptoms, as well. Have him check the crank sensor with a lab scope while heating it with a heat gun, from cold to hot. These are at their worst when hot.
Loren
SW WA

(This post was edited by Loren Champlain Sr on Nov 11, 2009, 6:20 PM)

Thanks for the advice. I did replace the #5 ignition coil but the codes came back again.(both P0355 and P1391). I was wondering why the code P0355 would come back if the ignition coil was replaced on the #5 cylinder. Could the P0355 be caused by anything else?