i got my check engine light in one day and took it to Autozone since they do free code checks. after several attempts to read the code the guy said he wouldn't be able to do it. i then took it to a dealership and they told me it would take a while to check it so i had to schedule an apointment. he tried to tell me the gas cap was causing it, but i already went through a 1/4 tank of gas before it came in. a couple days later it started idling rough and making a lot of noises and vibration when it was in reverse or drive only. i got out with the e-brake set and the exhaust was rattling a lot. the check engine light finally went off after i filled it up the next time.

does anyone know what it might have been? the gas or something? the exhaust still rattles BTW. any ideas what is causing that?

 

Hey i used to work for mazda, replace the spark plugs, they fowl out all the time on rx8s and more than likely it was your gas cap causing the check engine light. but get it done soon cause if your car goes on missing for two long you'll end up replacing the catalynic converter(s) and they about a thousand bucks a pop.

 

so you're saying the sparkplugs are causing the exhaust to shake, only in reverse and drive? that doesn't sound right to me. it doesn't do it once i start moving, only if i'm sitting still.

 

i dont really know mazda's but on anything not rotory yes bad plugs can cause rough idle. and im sure it would be much more noticable when in gear with the brakes applied due to the drag on the motor and the stealing of vacuum by the brake booster. but then again like i said i dont know much about mazda's.

 

looks like some warranty work in my near future.

 

go to the dealer and get some new plugs and check to see if there is a recall or service bulliten on the engine mounts. before i left mazda there were alot of rx8 owner complaing of excessive engine vibration at idle, and the tech department was working on a new design for motor mounts to lessen the problem. so i would check that out. and try to ask for some new spark plugs under warranty they had changed the design at least twice while i was there and that was in about a 90 day period.

 

the check engine light could have been from the gas cover because the same thing happened on my car, were if you dontclose the gas cap enough ( let it click for about 5 times ) then the light wil come on and it wont go off for a while, and for the vibration try and do what 93teg2b said and see what happens

 

thanks. it keeps coming in after i'm down to about 1/4 tank. i then drive it til its almost empty and fill it up and it clears again. IDK WTF is going on with that.