You might be losing your cat. I had misfires from cat failure.

If you feel a power loss under high load, and it keeps getting worse, then this will confirm it.

 

get this if it is your cat http://www.racingbeat.com/FRmazda4.htm

although how would clogged cat cause a misfire code?

 

Well i seem to have the same problem, my engine light comes on when i'm doing around 30 / 40 mph. Brought it to mazda on tuesday and they still can't find anything wrong with it.. Another issue is the darn tire pressue montor light. Seems like it has a mind of its own.. Tire pressure is good and tires are new. So they can't figuer that out neither... Any suggestions ?

 

i feel no loss of power what so ever and my cat only have about 2-3k on it. so i dont think thats the issue. but i will look into it if i cant get anything else to work.

https://www.rx8club.com/series-i-engine-tuning-forum-63/still-blinking-engine-light-202411/

created another post. and some other opinions are on there if u need help like me.

 

when i first purchased my 8 i was told that i can only use reg. motor oil. i've been reading some of ya comments and it seems like ya use synthetic. would i have a problem using synthetic?

 

Before you get flamed to hell and back: this topic has been beaten to death here, there are stickies on the subject. Basically, read those and decide for yourself... there is no conclusive answer.

 

Oil is classified under "Religious War" here on the forums. Tread carefully lest you lose the pants you came in on.