Can anyone help with surging problem.
At idle the revs cycle up and down and the car sometimes stalls when coming to complete stop. While driving at slow speed 30/40 klms the car looses power for a split second and the car will lurch. Have replaced Air Fuel meter and knock sensor without improvement.
This is an intermitent problem and can go for several weeks without a re-occurrence.
THis problem has existed for at least 12 months and has resisted all attempts by local Mazda dealer to find and fix.
Any suggestions welcome.

 

Not enough data!
What year car? What engine? How many Km.? Auto/Manual? Any prior history of "major incidents"? Regularly serviced? By whom? Check Engine Light on or off ? Any other fault codes?
When your Mazda dealer does a service, he should be running diagnostics tests, and if you ask for it, he should provide you with a hard copy printout of the results.

I'm getting bored with this, but here I go again; start by unclipping your air filter so you can flex the air duct between the filter and the engine. Check the duct very carefully for cracks/ splits. This is a very common fault and often leads to unnecessary replacement of the of the "air fuel sensor" (the mass air flow sensor, or MAF).
The extra air getting into the engine via any air leaks on the engine side of that sensor causes the engine to run lean, which is conducive to knocking under load, so that would also explain why the knock sensor was replaced too.
If you find leaks, replace the duct (about $50) or temporarily tape them up and see how things go.
Get back to this forum with your findings. Good luck.

 

Thanks for your reply.
My car is a 2000 model 323 Astina Hatch 1.6 manual qith 198000klms on the clock.
It has had regular book services but dealer has been unable to find and rectify problems after several attempts.
All they say is that it is intermittent and they cant find what is causing it.
They have run the computer over the engine without success.
Another suggestion that has been made to me by another mazda owner is that it may be the coils on the top of the engine ( two of them). BUt the motor does not play up under load as you would think if the coils were breaking down.
I will check your suggestions when I come back from holidays and post reply. I thank you very much for your response.

 

No problem;
I suggest you do a search for this topic on the Mazda Protege forum:

04-13-2009, 10:30 AM, by Adam S;

I have a 2000 Mazda Protege, 1.8L with 5 speed manual transmission @ 190,000 kms


Then, follow the replies and read oldeng post of 04-13-2009, 10:06 PM concerning diagnosis and treatment.

Your case sounds like a candidate for the stuff I suggested to Adam S.
Keep us up to date with how you're doing. Good luck.

 

Thank you very much for the link. I have printed it out so that I don't forget anything. Your reply was very informative and I am disapointed that the Mazda service staff at my local dealer is not as well informed as as "oldeng".
I will follow the steps and post a reply as to how effective it was.
Again thanks very much.

 

I am sorry that I have not added a reply to suggestions made but I have been waiting for my 200,000 klm service which is now due. I will keep you posted what the results are.

 

I have just had my 200,000klm service and all the suggested checks made without any luck. Nothing was found.
I will have to just keep trying.
Thanks for your input.

 

I had these problems
Surging and almost stalling "intermitent "- check fuel filter and fuel pump

The fuel pump, No pressure was being supplied to the fuel rail by the pump.
and fuel filter was very dirty.
My filter was blocked and the pump had stopped working properly.

I had it changed and the problem has gone, I had had problem for a long time, before this was fixed.
your problem may be fixed as you posted some time ago, just noticed this and added my experience with this issue.

 

Thanks for your reply. It has been a lot better since I had my 200,000klm service. I will keep your reply handy and will look at the items you suggested.
Many thanks
Gary.