true. if it gets rid of the lean code i'll just start using 89 from now on.

I did also clean my MAF a week or so ago. I wish I remember what day, and wondering if that helped at all. From the beginning I thought it was a bad MAF but didn't want to throw parts at it.

 

Update. The guy I had my engine mount done was all booked up this weekend and is far, so I went to a local place that my coworker recommended and got good recommendations on yelp. $45 diagnostic. I wanted to just do an independant diagnostic on my CEL without giving them any information to see what they said. HAd the car about 2 hours going through. I know I was supposed to try out a fuel pressure test and some of the gaskets and EGR I'll do that with my regular mechanic. They came up with a solution, I don't think their solution is helpful since it doesn't show up anywhere in any of the thoughts mentioned.

They found:

Valve Cover gasket leak (which I knew I had)

P0174 (Lean on Bank 2)

They said there was a radiator leak. I don't have any leaking fluids on the ground, they showed me where it was leaking/splashing. I'm not sure if this is a critical issue, I'll get a second opinion on this with my usual guy.

They recommended changing the spark plugs and then thinking it would fix the lean condition. They said there was a gap in the sparkplugs that may be causeing, and they fixed another car b/c of this. To me, it didn't seem to make sense. From my thinking here, I think this is just a case of throwing parts and hoping they fix it? They didn't find any vacuum leaks. I think if I did this, the CEL would just come back on again.

I am only going to do the valve cover gaskets, since I already knew I had that issue. The $45 diagnostic will go towards that anyway so I'm out of that and the price they quoted me was less than the mechanic I've been using recently (plus I'd have to sit there in the middle of nowhere on a Saturday morning waiting).


I found it odd only one bank was running lean now. And the CEL has been on for 2 weeks or so. Next weekend I'll probably do the fuel pressure tests. maybe the intake plenum gaskets. I'll talk to the guy and see what he has to say.

Regarding the Throttle Bottle Gaskets, I had the TB replaced at around 50k miles due to that TSB on them.

 

the Mazda 6s from the factory has a few flaws that may be small and some that can even lead to detrimental damage to the car itself. some of these flaws and/or shortcomings can usually but not always be fixed. But of course the manufacturer wont do it.

Anyway, the design of the Mazda 6s EGR system puts the tube of the EGR directly in the middle of the intake tract. Thats bad business. Basically it blocks the airflow to the cylinders. This compounded with a decently bad design of an Intake Manifold causes 2 issues.

1. one of the 2 cylinder banks will run significantly leaner than the other. How significant are we talking here?
--it has been documented that there is about a 5%-7% difference in fuel trims between the front and rear banks.

The above was a quote from: EGR Modification/Optimization: - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum
With that difference is why 1 side may be going on. I would do the above mod anyway.

 

Thanks. They got the parts late so I'll bring my car back in the AM to do the valve cover gaskets.

Since I'll have it there tomorrow anyways, do you think I should ask them to clean the EGR valve while they're doing that? Is it something mechanics normally do? Any suggestions on other things I could do?

Are the spark plugs just a complete waste of time to fix this code?

I'd look at the mod, but I'd feel more comfortable with the other mechanic that did my engine mount to do it though. but i guess cleaning the EGR valve might do something at this point?

 

The EGR mod probably will not solve your problem, however it may explain why 1 side is coming on sooner than other.
If I recall correctly (correct me if i'm wrong), you changed your plugs and later you had ignition coil problems, then you changed some coils. When you changed the ign coils you should also have installed new plugs (regardless if they were only a few months old).
If this is the case, change your plugs, intake plenum gasket seals, throttle body gasket/seal, do EGR mod (bring instructions with or or link), clean EGR valve. Inspect ignition coils. Re-set ECU. Inspect all connections electrically to ignition coils and make sure wires are secure.

 

It's good to know I'm not the only one. It sounds like you and I are having the same problem with our 04 6s'.

I've been experiencing, what I describe as, a grinding noise when the car is in drive and is cold. Like you mentioned before it gets worse when turning right and less noticeable when turning left and when the car warms up. Took it to the dealership and they said the top, passenger side engine mount was broken and the front lower control arm bushing is torn. Sounds like you had these (at least the engine mount fixed) and the problem went away. Good to hear. Makes me feel more confident in dropping $500 to fix.

As for the CEL; I have an Injen CAI and the CP-E black box. I had to disconnect the black box for Smog (Gotta love California) and of course the CEL came on. I disconnecting the neg battery cable to reset the ECU, took it to get Smogged, and crossed my fingers that it would at least stay off until the test was over. My luck it came on in the last 2 minutes of the test. But, it passed the emissions portion with flying colors. Took the CAI off, replaced it with the stock air intake, tried it again and this time the CEL did not come on, but it failed the emissions. After about 6 cycles the CEL did come back on. What are the odds that in that short amount of time something could go drastically wrong.

Took it to the dealer and they said my #3 cylinder was misfiring. Replaced all 3 coils (since they are in the back and a beep to get to) along with all 6 spark plugs. The car had a faint smell of fuel so they found that the #2 & #3 cyl's injectors were leaking along with a leak in the rear Exhaust manifold (Cat Converter?). Replaced all of that.

2K later my CEL is coming on again. My buddy has a reader and I'm going to pull the codes tomorrow.

Also, I want to apologize in advance if I offend you with this post. It's not my intent to corrupt this thread with my car issues. It just sounds like we may be experiencing the same thing and I'd liked to keep you informed with what "fixes" take place on my car in hopes that it helps you diagnose your issue(s).

 

the more the merrier.

oddly enough, I decided to clean my MAF today. After I did, the CEL went off (it had been on for the last 10 days. The last time I cleaned it, the code stayed off for two weeks or so until about 10 days ago). I did clean the MAF pretty throughly.

I'm wondering if I have a sporadically malfunctioning MAF sensor. I believe there is a code for the MAF sensor or it misreads due to some kind of contamination at odd times, but maybe something else is happening here. Its odd that the light shut off right after I cleaned it pretty thoroughly (although I would THINK it would take several cycles for it running ok to clear the code).

I too have to do a california smog before April when my tags expire. last time I had to do it, my car was running lean but the code cleared long enough for the test luckily. I had replaced the intake manifold gaskets and it fixed the problem for over a year to 18 months.

 

Goes back to my post #17 (Jan 19), spraying it liberally, drying it before re-installing. Maybe you didn't clean it enough the first time because it was so old & filthy. Maybe buying a new one is in the future (since the light went out right after you cleaned it). Clean or change your air filter and clean the filter box.

 

CEL Codes for MAF malfunctions are;

P0101 MAF sensor inconsistent with TP sensor ON 2 CCM
P0102 MAF circuit low input ON 1 CCM
P0103 MAF circuit high input ON 1 CCM

Not saying that a dirty MAF wouldn't throw a lean code.

 

Yeah. I did clean it VERY throughly every time I've done so, and let it dry, etc. I've done it a few times and two mechanics have. He tested it somehow using his scan machine and it seemed to be working properly, so many it has bouts where it works and doesn't work? Maybe me unhooking the MAF and hooking it back in did something? Who knows, it seems to be a mystery for the time being. I expect the light to come back on though.

I also opened the air box and filter, and re-closed it yesterday. any recommendations on where to pick up a MAF for the mazda? dealership price was way expensive, like $240 or something when I called I believe.

Getting my valve cover gaskets done right now. Not going to do the EGR cleaning until I monitor this MAF situation a bit more.