I have an 02 blazer and I am getting multiple engine miss fire. It runs very well except at idle a little rough but not terribly bad. I have changed the plugs, cap, roter and had a couple of service bulletins done, with no help. Any ideas

 

Are you getting any codes? If you get P0300, have a read through this thread:
P0300 Multiple Engine Misfires.
OR
The dreaded PO300 CAUTION LONG POST

Even if you are not getting any codes, there are a lot of suggestions in both of these threads.

You mention replacing the plugs, cap & rotor, but do not mention the replacement of the wires. Pop your hood at night in a dark area. Using a clean spray bottle filled with water, mist the wires and watch for arcs to ground. If you see any, replace the wire set.

 

My misfires (multiple ones) were caused by brand new Bosch plugs. Switch over to ACdelco plugs and it fixed the problem.

Brian

 

I did the same I now have AC delco's I will look under the hood tonight. Yes I am getting po300. I have also read the post Gator sounds like a funny guy.