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Mass Air Flow Sensor


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Is there anyway to tell if a mass air flow sensor if fried? I am haveing problems fixing my 996 with code P0303 and P0300. I have replaced the coils and plugs and even double checked to make sure they were all snug, but he car starts up dies or starts up and feels like its going to die. The motor shakes and smokes up near the driver side plugs, but not that bad, but I did not leave it on for long. The good thing is the CEL is off, but the car still is not right, it just either turns off or stays on while motor shakes and feels it has no power, revs under 1000rpm, and sometimes to keep it on you have to give it gas. So my question is could a bad MAF cause these problems? And would it make a difference to swap the coils and plugs on each side? a porsche tech said this might work, anyone with any knowledge of why this mught be? Thanks

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Is there anyway to tell if a mass air flow sensor if fried? I am haveing problems fixing my 996 with code P0303 and P0300. I have replaced the coils and plugs and even double checked to make sure they were all snug, but he car starts up dies or starts up and feels like its going to die. The motor shakes and smokes up near the driver side plugs, but not that bad, but I did not leave it on for long. The good thing is the CEL is off, but the car still is not right, it just either turns off or stays on while motor shakes and feels it has no power, revs under 1000rpm, and sometimes to keep it on you have to give it gas. So my question is could a bad MAF cause these problems? And would it make a difference to swap the coils and plugs on each side? a porsche tech said this might work, anyone with any knowledge of why this mught be? Thanks

no oil Loren, just really crusty with orange red rust color as well as the ends of the plugs too

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Is there anyway to tell if a mass air flow sensor if fried? I am haveing problems fixing my 996 with code P0303 and P0300. I have replaced the coils and plugs and even double checked to make sure they were all snug, but he car starts up dies or starts up and feels like its going to die. The motor shakes and smokes up near the driver side plugs, but not that bad, but I did not leave it on for long. The good thing is the CEL is off, but the car still is not right, it just either turns off or stays on while motor shakes and feels it has no power, revs under 1000rpm, and sometimes to keep it on you have to give it gas. So my question is could a bad MAF cause these problems? And would it make a difference to swap the coils and plugs on each side? a porsche tech said this might work, anyone with any knowledge of why this mught be? Thanks

oh , and the driver side coils were covered in oily grime/dirt..

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What do you mean "smokes up near the driver side plug"?? MAF sensor is common to all cylinders but you could try disconnecting it and seeing if that makes any improvement. I would also check the AOS and clean the throttle body/idle speed motor.

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If you have replaced the plugs and coils and you're still getting the same codes you can pretty much rule out plugs and coils. You could try swapping the fuel injectors to make sure you're getting fuel to #3 but injector issues are extremely rare. I would say the next step is to do a leakdown or a compression test to check the mechanical condition of the engine. A fault MAF is not going to cause a misfire in one cylinder. 90% of the time bad MAF will throw oxygen sensing faults.

Edited by PTEC
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If you have replaced the plugs and coils and you're still getting the same codes you can pretty much rule out plugs and coils. You could try swapping the fuel injectors to make sure you're getting fuel to #3 but injector issues are extremely rare. I would say the next step is to do a leakdown or a compression test to check the mechanical condition of the engine. A fault MAF is not going to cause a misfire in one cylinder. 90% of the time bad MAF will throw oxygen sensing faults.

Took the spark plugs out and found the tips covered in oil, looks pretty bad, CEL came back on and now only left with one code P0300.

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Correction: if you mean with the "TIP" of the spark plug, the part which is in the combustion room, than you have a problem.

yes the end of the spark plugs that goes into the motor are covered in oil, does this mean the motor is done?

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If the spark plug isolator and ignition coil are free of oil, you could have a more critical issue, let check the engine and the problematic cylinder in particular.

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If the spark plug isolator and ignition coil are free of oil, you could have a more critical issue, let check the engine and the problematic cylinder in particular.

the spark plug is completley covered in oil from the igniter going into the motor! and oil on o-rings and coils, the variocam area is also covered in oil and dirt. Thanks anymore input would be great. So do you think the motor is dead? Im towing it to dealer in LA, but they can't look at it until Thursday.

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A spark plug with the isolator covered in oil refers to leaking plug tubes (< MY03), a spark plug with only the central and ground electrodes covered in oil refers to engine/cylinder problem. I'm pretty sure your problem concerns only leaking spark plug tubes, i would start with that.

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A spark plug with the isolator covered in oil refers to leaking plug tubes (< MY03), a spark plug with only the central and ground electrodes covered in oil refers to engine/cylinder problem. I'm pretty sure your problem concerns only leaking spark plug tubes, i would start with that.

Thanks RFM! so that problem with leaking oil tubes would cause loss of power and the motor not to start ? What do the oil tubes look like?

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Please use the search button, this item is discussed here before. Wonder why the engine wont start on 5 cylinders Power loss is normal with one cylinder less.

"Is there anyway to tell if a mass air flow sensor if fried? I am haveing problems fixing my 996 with code P0303 and P0300"

"no oil Loren, just really crusty with orange red rust color as well as the ends of the plugs too"

"Took the spark plugs out and found the tips covered in oil, looks pretty bad, CEL came back on and now only left with one code P0300"

" the spark plug is completley covered in oil from the igniter going into the motor! and oil on o-rings and coils"

All very confusing IMHO.

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Please use the search button, this item is discussed here before. Wonder why the engine wont start on 5 cylinders Power loss is normal with one cylinder less.

"Is there anyway to tell if a mass air flow sensor if fried? I am haveing problems fixing my 996 with code P0303 and P0300"

"no oil Loren, just really crusty with orange red rust color as well as the ends of the plugs too"

"Took the spark plugs out and found the tips covered in oil, looks pretty bad, CEL came back on and now only left with one code P0300"

" the spark plug is completley covered in oil from the igniter going into the motor! and oil on o-rings and coils"

All very confusing IMHO.

RMF, took it to rusnak in pasadena and they said the problem is a " Valve Coil " and want $2800 parts and labor! is there DIY for this? and does the price seem steep?

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