02 Boneville Mis-fire (fixed)
 

Was hoping to get some ideas on what my current issue is with my 2002 Boneville SLE. The car was running fine when all of the sudden it loses power and throws an SES light. I was able to get the car home where I threw it on the scanner and got a P0300 code which is "multiple cylinder misfire". Not much help.

I checked all the wires and plugs which seem to be fine. I just changed them all about 3k miles ago. I'm thinking that this might be an ignition problem of some sort. Is it possible that one of the coild went bad. Anyone else encounter a similar problem? :nm

Thanks in advance.

sense it is multiple misfire and each coil is responsible for 2 cylinders it is very possible that a coil may have let go.or even the ICM

Thanks for the quick response.

When would the ICM be located?

It is directly under the coil packs..In fact the coils mount to it and set on it.You can either take the entire bracket off if that were the issue or just unbolt the icm and coils together from the bracket IIRC it is three 10mm bolts n the bottom..But i suggest testing before removal

Pull off the coils and the ICM, then clean up the surface the ICM is mounted to. Also make sure the tabs that plug in to the coils is clean.

Ok thanks. I have read before to stay away from Bosch plugs. Something about them not working well with the waste-spark ignition system the 3800 Series II has. I replaced the plugs with Bosch plugs before I knew this. Is it possible that this could be my problem?

It could be. I use autolite copper in mine and they work great.

I'm going to pick up some new plugs tomorrow and swap out the Bosch plugs when i check the coild and ICM. Is there a way I can check the coils to see if one went bad?

Here you go. https://www.gmforum.com/trouble-shooting-test-procedures-141/testing-coils-spark-plug-wires-278818/

Thanks! :)