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Dan, Technician
Category: Cadillac
Satisfied Customers: 24442
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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I have a 2005 cadillac sts,138k miles. Check engine light

Customer Question

I have a 2005 cadillac sts,138k miles. Check engine light came on and have codes po103 and po305.Engine has had a slight stumble or misfire before codes set.My question is are the two codes related, as they set at the same time or should i troubleshoot each one individually
Submitted: 2 years ago.
Category: Cadillac
Expert:  Dan replied 2 years ago.

Does the check engine light ever flash?

Customer: replied 2 years ago.
NO, The check engine light has not flashed
Expert:  Dan replied 2 years ago.

Have you tried to reset the codes since cleaning the maf to see if that helped?

Customer: replied 2 years ago.
I Reset the codes and the car was better for a couple days but is doing same thing again. the stumble is at idle or low rpms but at heavier loads power is good and it does not miss
Expert:  Dan replied 2 years ago.

I would recommend start by cleaning throttle body with cleaner and a rag. Spray the rag then wipe out throttle body good and also replace spark plugs if they haven't been replaced recently. Let me know how that goes or if you have more questions. Thanks.

Customer: replied 2 years ago.
Spark plugs were replaced about 10k miles ago.I'll clean the throttle body tomorrow and get back to you. thanks for the help
Expert:  Dan replied 2 years ago.

No problem, I'd also consider replacing at least the cylinder 5 spark plug if cleaning throttle body doesn't help. Let me know, thanks.