MSP 03 with missfire at high RPM or Boost

[GusDiaz]

Hi Guys.

I am a proud owner of a Mazdaspeed protg 2003.5. I have owed this car since new. I have a little problem. I have a misfire only at high RPM (over 3,500) or under boost. I have changed the spark plugs and wires, but still have the same misfire. Do I need to check for a code??? is there any other possibilities that I am not looking at. The car runs good under idle and when normally driven. When you ask boost to it then it starts having the problem.

Thanks, Gus

 

[GusDiaz]

Ok, finally found the problem. NGK Iridium 11 Spark Plugs gap at 0.045. As soon I gap them at 0.030-31 the problem was solved. Ran it for 15-20 min at the interstate. No misfire at all. Good vacuum at -22. Good boost at 8.5. will inform is the problem happens again.

 

[protege3690]

yea chances are it was probably was the gapping on the spark plugs that was causing that.