[tredawg11]

I have a 2000 STS and my service engine soon light is on. The code says the #3 cylinder is miss firing. I've changed the sparkplugs, coil and injector and it's still miss firing and reading the same code. Does anybody have any suggestions? The car idles a lil rough but drives fine when on the road. I can definitely feel and hear the missing!

 

[johnny kannapo]

Did you change the #3 boot?

 

[jimsbox]

There is a spring in the boot, make sure it is intact, carries the current from the ign module to the plug. You can swap the coil pack/ignition module between the heads and see if the Po3xx follows it.

 

[tredawg11]

Yep! Changed the boots. Some of the springs was alil rusty.

 

[RippyPartsDept]

are you using acdelco plugs?

 

[johnny kannapo]

I would look at how the module is making a connection to the coil.

 

[Pete315]

could be the wiring for the injector. I had to replace my fuel rail wiring which fixed my problem.