Hello, I am in the uk & I own a 2005 Mazda 6 1.8 petrol. I have been having a slight problem. Shame because I love this car. Hopefully somebody may know what my problem is. Firstly I experienced what I thought was a misfire when pulling away under load, low-medium revs, in the middle 3 gears mainly. i.e. when pulling off of a roundabout type driving. Not totally sure its a misfire, but when im driving through the gears its not running consistently. It feels like its surging, on off on off until momentum carries the car out of it, it then drives fine. If i boot it then the surge doesnt really happen. The car ticks over fine when idling. I am getting no code from diagnostic machine(snap on machine, not a cheapy one). I have run some injection correction fluid through in the fuel, to eliminate a dirty fuel issue. No change. So I had new spark plugs fitted, Platinum ones, not cheap. No change. Reading on some forums it sounds like it may be a lambda / oxygen sensor issue/fault. Does anybody know whether its possible to have a fault of this nature but not give a diagnostic code? Sorry for the long post, I have tried to keep it to a minimum but pass on the facts at the same time.

Thanks for taking the time to read this.

Paul

 

You should have a code if the check engine light is on, and a check engine if an O2 sensor or anything being read by diagnostics has an issue. I'd suggest clean the MAF sensor with approved MAF cleaner. Make sure the air intake plenum is clean, no cuts/holes ect.

 

Hello, and thanks for your mega fast reply. I have no fault lights on the dash. Where will i find the the MAF sensor? & where is the air intake plenum? Sorry That i dont know where these are. Im a novice.

Thanks again

 

Hi, Just to let you know I found the MAF sensor, using a photo step by step online, so i will try that tomorrow morning.

Appreciate your advice

 

Hello, did you solve your running problems ? I also have a UK spec 1.8 petrol. The other week I cleaned out my throttle body, maf sensor and the little sensor that sits inside the plastic intake manifold. When I restarted my car afterwards it wasn't responding to the throttle and the idle speed was hunting up and down. On another site I was told to disconnect my battery for 10-15 minutes, this resets the ECU. It worked, my car idles smoothly now at 800 revs. You will have to reprogram your electric windows but that's easy enough to do.
I hope that helps you.

 

Hi. Thanks for your post. I have cleaned the maf. Huge difference. Not quite 100 % but close enough for a mileage of 130, 000. How do you do the throttle body. Was it easy? Also how do you re program the windows. As I noticed they dont automatically go up or down with the button on the door anymore.

Thank you

 

Oh and where is that little sensor you mentioned on the plastic intake manifold. Thanks

 

Thought I would post this as I have solved the problem. Firstly I cleaned the mass air flow sensor (DIY: MAF Cleaning - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum). Then cleaned out the throttle body (FLUID's blog: Mazda 6–How to clean throttle body)

Hope this helps anybody with the same problem.

 

I had a look at Fluids Blog and do not agree with his cleaners. i would never recommend a brake cleaner for any electrical components. it can be pretty harsh, and it's not worth the risk. When removing the throttle body it is always best to replace the gasket in behind as it gets dark and hard from egr crap. I like to partially remove throttle body and catch all fluid with rags/paper towels. It is a must to disconnect negative battery terminal or using an assistant as per this video. Re-start when maf is dry, and let idle for 10 minutes before driving. ECU re-learning has begun and will continue for at least 50 miles.
VIDEO: http://www.motorweek.org/features/go..._idling_issues

USE the following cleaners:

 

Thanks for the info. I will bear in mind next time. I used a little brake cleaner to removed the carb cleaner. But not much. Seems ok. My throttle body was thick with rubbish. So im glad I cleaned it. I may change the gasket then. For the sake of a few quid. Thanks for your advice.