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Expert: - 7/12/2009


Question
i just change plugs on a 2000 cadillac dts 32 valve northstar engine1now the engine is still running ruff and the service engine soon lite is flashing.what would cause that

Answer
Hello,

The check engine light flashing is only a symptom telling you something is wrong with the computer and or components involving the emission system.

There are far too many problems that can cause the light to flash.

You can go to a parts store and purchase a code reader or you can take the vehicle to a service garage (not a dealership) and have the vehicle scanned for error codes. The codes will tell you what is malfunctioning in the system and then will tell you what part(s) failed.

If you try to guess what is wrong, it's chasing ghosts. The light illuminates leaving a code or codes telling you what circuit is not functioning.

The car will run rough with the light on and a tune up will not fix the problem.

Good Luck!

Rob

Cadillac Repair

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Rob Painter

Expertise

Alarm system questions cannot be answered on this forum. These systems are not what I can answer. Without being physically at the vehicle and not knowing what kind of electrical service has been done on the vehicle, there is no possible way to give an accurate answer over the internet. My expertise is in Ignition/key based anti-theft systems. These issues include GM VATS (resistor chip in key blade) PASSLOCK (MRD)-ignition lock rotation based, no special ignition key and the PKIII Transponder (computer chip in key) systems. These systems are not alarm based and are integral with the starting of the engine. This is why I cannot diagnose alarm problems without physically looking at the vehicle: Alarm systems are a completely different annimal than ignition key/lock based anti-theft system. Many alarm questions come from vehicles 10 years old, and since older, many hands that had been involved over the years.I am an expert in all GM factory (ignition/key based)systems. Alarm system questions pose to many situations beyond my knowledge as to what has been done to the vehicle over the years. Some guy may have actually wired the stereo into the alarm system. Who knows? Over my past 30 years in vehicle wiring repair, I have seen unbelievable wiring disaters done by guys that consider themselves "mechanics." I have seen stereos and alarms intalled using surgical tape. I have seen modules burn up, un-fused circuits, wiring jambed between the doors and even lamp cord used for a starter kill. To answer alarm questions over the internet without examining the vehicle is like asking; What does it take to remove a dent?

Experience

Education/Credentials-ASE certified. 11 years with a GM dealer and 17 years with a repair facility dealing with only the repair of theft recovered vehicles.

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