Mazda Repair Questions? Ask Mechanics for Answers ASAP
Welcome, I'm Chris (aka Moose) I prefer to work when others don't, I am here around lunch and after dinner till after midnight.
Is the idle high, low, going up and down?
Is this misfire at idle or while driving?
If you hold the throttle at 1000 rpms with throttle pressure can you prevent the misfire or idle fluctuations?
While running if you plug this valve by hand is there vacuum on it?
If you remove the the vacuum line and plug it does it run better?
While running, spray short bursts of flammable brake cleaner all around the intake and vacuum hoses to see if you find a vacuum leak. If you spray a leak the idle speed will change. Let me know those results.
This is my 1st answer, but does not have to be my only answer. You the website and myself expect you to have a great experience with my help. Please let me know if you are pleased by selecting a star rating above or by replying and saying your pleased. Not rating or rating 1-2 stars does not benefit you nor me in any way. Follow up and reply as often and when needed, there is no extra charge to do so.
Hello again Chris here,
Has the fuel filter not been serviced regularly every 30k?
Is the fuel pressure low?
To test the pressure you connect a pressure gauge to the fuel supply on the injector rail.
You can remove the upstream O2 sensor and take the vehicle for a drive to see if it runs better with another exhaust exit.