I have a 2004 Cadillac deville that has the P0300 code and flashing check engine light on it was missing and sputtering. I narrowed it down to what I thought was spark plugs and 2 bad coils, changed them and it helped for awhile (about two miles). Now it is missing again and has the flashing check engine light and po300 code again I checked for vacuum leaks and didnt find any. I checked for bad connections and didnt find any. I checked the EGR valve to see if it was stuck or blocked and it is fine also. And the exhaust smells rich, but not like rotten eggs. I also had a new fuel pump and filters installed about 6000 miles ago. I also narrowed it down to cylinder #7 on the scan tool and the cylinder seems to be dead and completlely misfiring, I then swapped fuel injectors on #7 with 6 and #7 still is misfiring. I put a new ignition coil on # 7 cylinder also. I also checked compression and it was fine. I checked for spark and it was good, Any Ideas? Ignition module? Crank sensor? Cam sensor? Bad wiring harness? It is running very rich also.
have the same problem?
Sunday, May 16th, 2010 AT 2:31 PM