Intermittent Problem (doing my head in)

Bighouse

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Can anyone help - my ML320 was spluttering with loss of power - I fitted a new airflow sensor and it ran perfect again for about 3 weeks - but now it runs fine for a bit - then it starts to splutter again and not rev properly - then it runs fine again:confused:. I thought it may be the air filter so I fitted a new one but it made no difference. I'm not sure but am I right in thinking the Mass Airflow Sensor is something different from the Mass Airflow Filter? If so could the MA Filter need cleaning? - where is it and how should I clean it? If not what is the problem likely to be? Any advice would be greatly appreciated.
 

jibcl500

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did you replace it with a bosch MAF or something off ebay, if not Bosch then thats probably the reason.

jib
 
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Bighouse

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Hi Jib
I replaced it with one from Euro Car Parts - I dont think it was Bosch - do you think it could be an intermittent fault with this part rather than something else?
 

Legoman

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check the ignition system sounds like similar prob as my car , people always forget the plugs , leads , rotor arm and dizzy cap , start with the cap and arm , after seeing the condition of mine seems there prone to corrosion. not sure what the ignition system is on your car btw , but the fault you describe suggests its misfiring.
 
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Davey

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Check the coolant temperature sensor, remove it and check its not corroded or gunged up.. if its starts failing it will cause warm or cold running problems.. EGR valve is another goodun, as they start to fail they get stuck open causing random warm running issues with not ECU errors.

check the ignition system sounds like similar prob as my car , people always forget the plugs , leads , rotor arm and dizzy cap , start with the cap and arm , .

Its a 1999 car with EFI.. ;)
 

jibcl500

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Could be the coil packs failing or failed, easy enough to replace, always good to replace bosch with bosch.
some of these cheap MAF could cause more expensive problems later, if you look at the sensor on a bosch MAF and then the sensor on a none branded MAF you will see a difference.


jib
 

television

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As Jib we have had many post where the real thing has fixed the car
 
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Bighouse

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Thanks guys
I must admit it hadn't crossed my mind that the sensor I fitted could be intermittently dodgy - it was the cheapest available - Im going to try and get a replacement sensor and give it a try - if it doesnt work I will upgrade it to a Bosch and give that a whirl. My original was a Bosch and I remember it was quite different (unfortunately I lobbed it in the bin the other day). If that doesn't work I will look at the other things mentioned. I will let you know what happens. Cheers.
 

jibcl500

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find the bosch web site and then find the nearest service center to you, MB want about £247 + vat for you MAF bosch retail £139 inc vat!!!!

jib
 

Davey

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Before parting with 290 quid, I'd try some cheaper routes first.. i.e. plugs, CTS and blanking off the EGR. even fuel filter! And to be honest an AFM isnt any mystical device they are all just chinese made bits of electronics :) And I think Bosch are jokers when it comes to list prices.
 
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Bighouse

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Quick Update - I have just fitted a replacement sensor and on road test the car seems to be running fine again. Proof that the cheap MAF sensor that was only a few weeks old was faulty - unfortunately I have only replaced it like for like at the moment but I will definitely upgrade to a Bosch sensor if this one plays up. Thanks for your advice guys.:)
 


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