2004 Cadillac SRX Runs rough with misfires

62CARGUY

MEMBER
2004 CADILLAC SRX
3.6L
V6
RWD
AUTOMATIC
65,000 MILES

My car has 65k on 04' cadilac srx and runs rough. I am getting several codes, p0300, p0301, p0303, and p0304. I have replaced ignition coil on cylinder 4 on drivers side, which seemed to have the most misfires, but it seems to not make any difference. I have tried to check for vacuum leaks, but I am not very familiar with this engine. I am wondering what might be the next step to problem solve this?

5 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

I would start with basics. Replace the plugs and check the other coils very closely

Roy

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Sunday, December 13th, 2015 AT 7:38 PM

62CARGUY

MEMBER
3 POSTS

I have already changed plugs, still the same misfire. If iM looking at coils, what should I be looking for if they are bad? Is there a way to test them?

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Sunday, December 13th, 2015 AT 11:40 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

Remove the coils and check the boots for any signs of grey marks that indicate burning inside the tube.

Roy

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Monday, December 14th, 2015 AT 6:08 AM

62CARGUY

MEMBER
3 POSTS

I have checked all boots and they all look in great shape. I have also switched the ignition coils around to see if that made any difference. I still keep getting the code p0300 and p0304. Both oxygen sensors have been replaced up by engine, and that has not changed anything. I am not going to replace fuel filter next and then possibly #4 injector. Any ideas would be greatly appreciated.

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Thursday, December 17th, 2015 AT 3:43 PM

ASEMASTER6371