I started noticing hesitation at 7-8k for the past few days. Car has 18k miles. A red line 1st gear shift would yield a 2nd gear that was weak to start and felt like I was missing 50 horse. A redline 1st shift will normally yield tires barking when 2nd engages, but not anymore. When idling, a redline rev produces the same effect as a 9.5k fuel cut off, only now its happening at 8k. So, coils, plugs, MAF maybe hmm. P0300 cel comes on, random misfire. Ok goto mazda. Cables all fine. We test BHR coils, they are fine. We decide the plugs are going out, and I make an appt next week to do 20k mainteneance check and replace plugs.


Today on way home from work I go WOT in 1st with no hesitation, and the tires are burning rubber on the shift. Whoa, I got my power back. I repeat several times and the problem is now gone. I cleared the cel and its not coming back on. Strange to me. Any ideas?

 

not spark plugs I bet. Probably the knock sensors coming on board and retarding your timing?
You may have gotten some bad gas? Was your operating temps the same between the two occurances?
OD

 

Yes temps were the same. I usually always fill up with BP premium. But the last time I filled up (right before this incident) I went to shell and filled up. Maybe it was the gas!

 

never had problem with BP.

 

you really have to watch gas now a days. I bet that was it. The ethenol content varies so damn much and with that the water will too. Also if you premix and the ethenol content is higher than it should be, the pre mix oil will not like that..

 

You used Shell V-Power? Never had a problem with that but I will monitor in case I experience the same issues. Thanks for making note.

 

I have had the same problem before, replaced plugs and all was good. The issue would come and go. One day it would be fine, the next the issue would happen again.