I just got my rx-8 about a month ago it didn't run right right so I brought it to the auto parts store. 4codes came up the o2 sensor something with the intake, cylinder 2 was miss firing and the crank sensor was bad. I brought it to a mechanic and they really didn't know what it could be they said we should do the crank sensor and the plugs so we did it still stalls. They told me to try new coils I put new cools in as well. The miss fire in the 2nd cylinder went away and it is still stalling. Does anyone have any ideas on what it could be so I dont keep waiting money doing the wrong things. I am limited on money so it is hard for me to do multiple things at once. And also when the. At is Idoling it revs down to like 800 rpm then revs up to 2500 all
By its self. Any thing would help
Thanks in advance!!

 

How many miles on your car? Did you just change the plugs? Is it auto/ man? Any modifications?

I suggest reading the new owners stickies (stickies are located at the top of each sub-forum). Doing that will lead you down the right path of troubleshooting.

 

It just broke 99k. It's a manual and it has custom exhaust aftermarket oil lines and a chip that's all mod wise

 

And I just changed the plugs yesterday

 

What chip does it have?

 

The rev surging sounds like a vacuum leak, check that there isn't a loose vacuum hose somewhere.
It's a good thing you changed the coils, they can lead to big problems.

Aftermarket oil lines? That's unusual.
Unless the chip is a Cobb AccessPort with a proper tune, you'll want to remove it.

 

Did you have the battery off at all while doing the plugs and coils? If so, the ECU has reset and it is relearning the fuel trims. Symptoms seem to match up well with that if the idle is surging and you're stalling often.

 

That's weird because there isn't the original vacuum hose on there it's a clear hose with tie straps holding it on. The mechanic told me it's nothing to worry about. And I'm not sure what kind of chip it has just people told me it has one and the guy I bought the car off of said it had one

 

I changed the plugs after it started stalling. But no the battery was in

 

That clear hose could be causing your idle problems, that looks like it could leak easily. It's not even held on with proper bands, just zipties. If your mechanic is OK with this, don't go see him any more. It looks like the previous owner broke the plastic tube that sits in the accordion tube and normally accepts that vacuum line, and jerry rigged something in place. I'm sure a junkyard or some folks here could help you with getting a new tube. Heck even Mazda could.


It also looks like the VFAD vacuum line isn't in where it should be, in the little clip to the right of the accordion tube. Maybe it's just not clipped in, but check that it is either there somewhere and connected or the VFAD has been removed and the line properly capped. It can't be open to atmosphere.

 

Thank you I'll give it a try

 

MRW I see that photo:



It's a good thing you rescued that poor '8 from it's previous abuser, Brandon.

 

So much effort to just half *** something. I don't understand that mindset.

 

Should I only put premium gas in it?

 

Yes.

 

Have you started reading those stickies, like I suggested?

 

Nobody has said it yet. So. go get a compression test from a Mazda dealer or a shop that has a rotary specific tester. You can chase maintenance problems all day. But if the motor could be toast, you're wasting your money.

 

Also when I bought the car it has a cracked front bumper if you guys know anyone that has a blue bumper tell them to message me please. Thank you

 

wow.

 

Oh man, good luck with that.

 

I hate to break it to you, man, but you are in for a world of trouble.
That car has not been taken care of and you're going to keep finding **** that the previous owner did wrong or didn't do at all.

 

It's fine I only paid 600$ for the car he told me it was mis firing on cyl 2 which it was I got that fixed but it's still not running right. But I won't take a loss on the car lol people are selling these cars on my local craigslist with blown engines and they don't run at all for 3k

 

Well the wing alone goes for $1000+, if authentic. So that's a good deal, just clean up the previous owners fails, including the $1200 bumper (if authentic), and have a fine car.

 

I brought it to a shop they told me that cylinder 2 was miss during so they told me to get the 2nd coil so I'm going to get that

 

In your first post you said you had already done the coils?
Yes it's the correct thing to do when dealing with a misfire, and you change all 4 coils, not just 1 or 2. But if they were just changed, then this is a different story.