I fixed several problems all by changing my plugs.

I used to have a low-end stumble and low BLMs. Well, I think the stumble was caused partly by me trying to tune the BLMs back to 128 (causing it to run lean some of the time, off-idle, etc.).

Anyway, I put in the new plugs, put my tune back to stock (injector constant from 33.5 to 31.7 for my 30# SVOs, stock MAFS tables), and my idle BLMs are RIGHT ON 128! :0

I can't hardly believe it! All this caused by plugs!

And the most amazing part... the plugs LOOKED fine when I took them out. No gunk, a lightish tan color, like everything was fine. But they were causing all the problems.

So, try replacing your plugs if you've had similar problems.

 

Interesting, were they copper or platinum and how many miles were on them?

 

They were Autolite 104s (copper), with probably less than 5K miles on them!

I'm thinking they could have been "fouled" by my stock injectors going out awhile ago... but again, when I pulled them, they looked like every picture I've seen of a "good" plug.