Still having stuttering problems
 

I'm still having problems with my car stuttering at cruising speeds. It's been happening for a little over a month now and I just can't find out why.

It usually happens around 2,500-4,000 rpms under low boost. It's never happened under WOT and I've never seen any KR or low fuel pressure. When it started I was on my 25% e85 tune, but that wasn't the culprit as I've been experimenting with my stock and other 93 tune and it still happens. I've used different gas stations. And I haven't installed anything in the last year so I don't think I have an air leak.

So I checked my plugs and they seemed ok to me. What do you guys think? I read on a random google image for bad spark plugs, that a clean white looking insulator could be a bad thing? What do you guys think?

http://i.imgur.com/lsSNs6p.jpg

And I uploaded some logs in my first thread and no one seemed to see anything out of the ordinary.

I've gone through 4-5 gas tanks of straight 93 octane gas and no change. Is my only other option to check the spill valve in the fuel pump?

Thank you for everyone that has helped in the last thread.


other thread for reference

http://www.mazdaspeedforums.org/foru...el-cut-146714/



I also forgot to mention I unplugged the o2 sensor for a little while, but I didn't know if it was safe to keep it unplugged for long... And I'm sure it happens, but bad o2 sensor on a 21k vehicle?