6 MPS has developed a slight miss

[Penguin740]

It seems my wonderful 6 MPS has developed a slight miss in the engine.

The miss is noticable when on moderate throttle and low boost. It's not a strong miss but annoying.

On full throttle and idle it appears to be fine.

Does anyone have an idea of what this could be cause by? eg Could a bit of injector cleaner possibly fix it? Could it be just the realtivly new exhaust and pod filter playing with the mixtures (which will be sorted when Chiptorque chip it) on the otherwise standard car?

Any help would be appreciated before I take it in to Mazda to have it looked at.

[shakespeare]

Hmmm, not sure here, probably need some more info - What RPM and in which gear does this occur? I tend to get with mine (if I forget to downshift) a bit of mild hesitation when I accelerate around 2000rpm in 3rd or above, so now I always downshift as you don't want to put excessive load on the motor.

[Mr Nasa]

intesting, is it like a jolt?

[Syd_Chrome]

If it is like a flat spot, it maybe a dirty MAF sensor. Worth a look?

[Ranton]

Maf Sensors or dead 02 sensors account for more problems than people care to think

[Penguin740]

I'll have a look at the MAF sensor first.

The O2 sensor could be a possibility as well due to the exhaust shop finding that the person who removed it at mazda had stripped the thread and is currently holding on with just a few turns. 2XS was pretty sure it would be fine until I find a replacement.

[Penguin740]

I cleaned the MAF and IAT today (as well as 2 other Mazda's in the carpark at the time).

I have gained throttle response back which had dropped off and can't seem to notice any roughness anymore. I will keep an eye on it and see how it goes after a few days.

Thanks all for the help. I'm off to hunt v8's.....

[LILZLR]

Maf Sensors or dead 02 sensors account for more problems than people care to think

+1 Very true. .

[Penguin740]

Well it appears that the miss is still there and seems to be getting worse.

Shakepeare, The miss is most noticable between 2500-3000 rpm in 3rd and 4th gear.

I suspect it is occuring lower as well but aggree with you that I prefer to keep the engine well above 2000rpm.

Any further ideas?

By the way how do I check or clean on o2 sensor? Can a complete novice do this job?

[spastic]

could it by any chance be boost cut?

---------- Post added at 10:06 AM ---------- Previous post was at 10:05 AM ----------

Ryan's mps "mpsi" was getting boost cut in his car b4 chip torque tuned it for him?? just an idea

[Penguin740]

I don't think it is boost cut, as my testing has been on light to moderate throttle so the engine is off boost or just coming on to boost.

Thanks for adding another possibility though, any help is appreciated.

[spastic]

ryans can get boost cut from light exceleration to full throttle so it was just a bit of help?

[Penguin740]

Wow. OK I won't write this off as a possibility yet then.

[spastic]

has your car been for a chip torque tune yet?

---------- Post added at 10:45 AM ---------- Previous post was at 10:44 AM ----------

when ryans went in the first time it didn't get boost cut then when he got it back they safe tuned it and it had boost cut all the time now he has had the tune finished i'll have to ask him about it weather it still has it

[Penguin740]

I haven't had the tune yet as I am waiting for the warranty to run out (1 month to go!).

[Penguin740]

Well the miss is now not a slight miss.

I was driving today and the car got a really bad stutter on medium throttle between about 3-4000 rpm. It then put up a check engine light.

Time to take it to Mazda to see if they will fix it under warranty. I think it might be plug leads or coil pack perhaps (I had a similar problem on my VR4 and new plug leads fixed it).

[Penguin740]

Coil pack it is!

Mazda confirmed a Cylinder 2 misfire code, and have swapped the leads between cyl 1 and 2 and asked for me to keep an eye on it.

I assume they want me to replicate the same check engine light but on Cyl 1 to confirm if it is definitely the coil pack and not the leads.

It still has subtle misses and hesitations. Mis fired badly within 5mins of the dealer but I was in hurry. No CEL unfortunately and no bad mis-fires since. Back to Mazda.

[chiumell]

I have suffered very similar problems on my Mazda6 MPS. What did you work out in the end was causing the misfire?

[Rayd]

interesting ...

keep us updated on how it goes bud and good luck!

[Penguin740]

I have still not solved the problem with my car. Sorry.