dieselrx8

After warming up...headed down the road. She starts running rough and the CEL comes on then starts flashing...it smooths out with no CEL. Turn around bring her home and it then does the same sequence. Parked it and called a buddy with an ODBII reader.

The codes i get are as follows:
171 - running lean
300 - misfire
302 - misfire in bank 1
171 - running lean

Can anyone help with a diagnosis?...i really don't have a great resource for local shop or dealer. When i called Browns Chantilly Mazda in VA (some other members recommended) the guy i spoke with didn't know squat and started rattling of ridiculous diagnostic costs ($300 for compression check) etc.

i know i may have to go the dealer route but i'd like to see if anyone has any experience with these codes so i can make sure the repair is on track and they don't just start throwing parts at it. I'd also welcome any recommendations on repair facilities.

Jon316G

iTrader: (1)

What year is your car and how many miles are on it?
Did the CEL occur at high RPMs (like while you were accelerating above 7K RPM)?
When was the last time you changed the ignition components (coils, ignition wires, spark plugs)?
Those are usually a good place to start and easy items to replace yourself so you don't get ripped-off by the dealer.

dieselrx8

Jon

its an 04 with about 73k miles on it...i can't say if they've been replaced or not as i'm not the original owner.

I thought about doing the coils and wire pac first myself...i have access to a lift. Just wanted an opinion if those seemed to be good first starts...

Thanks for the input

now to secure a service manual LOL....

Thanks again man.

Jon316G

iTrader: (1)

Instead of the service manual, search around the forum (specifically the DIY section).
Lots of helpful information there.

Here is the DIY for changing the coils:
https://www.rx8club.com/showthread.p...ht=spark+plugs

And the DIY for changing the spark plugs:
https://www.rx8club.com/showthread.p...ht=spark+plugs

Service Manual can be found here:
https://www.rx8club.com/showthread.p...service+manual

dieselrx8

Thanks again!

So do you think replacing those first is a good first step...i think the cat and O2 sensor are ok since i didn't get codes in that realm....

i'm just not sure what would throw a lean reading...maybe the coil shooting to hot a spark?

seriously i see you post in a few tech threads i do appreciate the help.

dannobre

iTrader: (3)

Look for a vac leak as well.....If you have an aftermarket intake check the VFAD vac nipple....

If it falls off it will throw a lean code...

Jon316G

iTrader: (1)

Do you have a noticable power lose above 6K RPM as if you were stepping on the brakes?
If so, then it could very well be the cat.
Usually the plugs are the first to be changed out, but since you have 73k miles on the car and not certain if the coils and wires have every been changed-out, you might want to consider doing them all just for peace of mind.

Jon316G

iTrader: (1)

+1 Good call dannobre.

Mazurfer

Jon gave you just about all the info you could want and the links.
Definitely do the coils and plugs first.
But................you might as well do the plug wires at the same time.
When you're ready to buy some. Search and you will find some decent prices with some of the vendors on this site. They will beat the crap out of pretty much any dealership. Also.......you could consider a BHR ignition system if you wanted. Search for that as well.