2004 Cadillac Deville Repair Question
2004 Cadillac Deville P0300 code
2004 Cadillac Deville V8 Front Wheel Drive Automatic 120000 miles
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.
A random misfire P0300 normally is caused by vacuum leaks and bad fuel
68 questions asked
I sprayed carb cleaner everywhere, all around the hoses, boots, intake and fuel injectors, checked all the hoses, and nothing changed. Does water work better for checking for vacuum leaks?
1 question asked
Carb cleaner or WD40 will do when you hit the leak the engine will run smooth indicating where the leak is-You could also use a vacuum/pressure tester
68 questions asked
Im having the same problem right now and i would be interested in what you find Chris im getting a rich exhaust smell and i currently drive a 2004 cadillac deville with 67k miles and i've checked for leaks and pressure and nothing yet i got the same code p0300 and it doesn't seem to be misfiring im thinking it could be one of my spark plugs i found a bit of moisture by one of them but i cant be sure any advice?
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