Help me understand my fault codes please

[Savath]

My car is a 2009 b8 Quattro and a couple days ago it started to shake when I drive and threw out esp and emergency brake malfunction ....I'm thinking it could be misfire so I checked the spark plugs and cylinder 1 spark plug was wet so I cleaned the plugs put them back in and switch coil one and coil two around and drove it to work today same problem. ..when I got home I checked the codes again and and the spark plugs all were dry but it's still show cylinder 1 so I switch the coils back to their original spots coil 1 back to cylinder 1 and coil 2 back to cylinder 2 cleared the codes started the car up for 10min and check the codes again and it still says cylinder 1....so I'm not sure if it's my coil that is bad or could it be something eles

[van462]

Does the exhaust have a gas smell to it?

[Savath]

I'm not sure how to post pics cause I'm using my phone but the fault codes are in my gallery.

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Yes it does

[o1turbo30v]

Esp and brake malfunction warning lights = bad mass air flow sensor.

[Savath]

Would a bad MAF sensor cause the misfire?

[van462]

http://www.audizine.com/forum/showth...t-leak-testing Start at picture 10 to isolate PCV or intake manifold as the lean code source. If the problem still occurs with the intake manifold port covered then check http://www.audizine.com/forum/showth...ntake+manifold This usually also generates another code for intake flap out of poition.

You are showing faults for every cylinder so likely hood of it being a coil pack or injector go down dramatically. At idle (cold engine idle) the ECU is using baseline maps to calculate air and fuel vs using sensors. These are also fail safe setting in case of sensor failure. MAF is less likely. If you had a good idle but misfire with throttle applied that points more to MAF. But an easy test is to have the car off, disconnect the MAF plug. Start the engine, if it the problem goes awa, then MAF is highly suspect. Do not apply throttle, besides setting off lots of fault codes the engine has no way to calculate fuel delivery and will stumble badly. It will also trigger a temporary safe mode and not allow boost.

[Savath]

Thanks van ... I replaced the pcv a few months back so I don't think it's the pvc and I did the MAF unplug and it still idle bad I don't think it's the MAF. And the intake manifold plug is still in place... My R8 coils should be delivered tomorrow so I'm gonna replace the coils and spark plugs tomorrow I'm hoping that will solve my problems.

[van462]

Even if the PCV is good, a failed rear main seal will cause the same symptoms. Also if you replaced your PCV to the newest revision without the accompanying software upgrade you will also get lean fault codes. A lean condition can cause misfires , but misfires cannot cause a lean condition.

[Savath]

Ok thanks that's good to know.... so how would I check the rear main seal? And when I take the oil cap off I do have vacuuming what does that mean?

[Savath]

I've been searching through the forums and someone said it could be bad gas could this be the cause because I've recently switch to SAMs club gas to try and save some money

[van462]

Follow the steps in the first link and remove the hose from the intake manifold going to the PCV. Block off the intake manifold with a ziplock and some tape. This easy test can save you lots of money in buying the wrong parts. There is no easy way of checking the rear main seal. When it usually fails it will also leak out oil; and you may see oil coming out between the engine and transmission. If sealing off the intake makes the car run smooth and the codes reset and stay of then you eliminate coil packs, injectors, maf, and the intake manifold itself.

[Savath]

Ok thanks

[Savath]

Yeah that didn't help lol

[Savath]

Car still idle bad

[bluefox280]

My car is a 2009 b8 Quattro and a couple days ago it started to shake when I drive and threw out esp and emergency brake malfunction...

Do you scan the ECU with a VAG-COM / VCDS? If so, what were the exact fault codes?

...I'm thinking it could be misfire so I checked the spark plugs and cylinder 1 spark plug was wet

Cylinder #1 plug was wet with what exactly? Fuel? Oil?

so I'm not sure if it's my coil that is bad or could it be something else

If you swapped coils and the misfire did not move with the suspected bad coil, its not a fault ignition coil.
Time to look at the plug gap, plug continuity, and check the ignition coil wiring from the connector to the ECU.

- Erik

[Savath]

I'm using Carista to get my codes.

Not sure if it was wet with fuel or oil but when I replaced my spark plugs it was not wet the second time.

So I replaced my coils and spark plugs that didn't help ...so I decided to to try the maf test again but this time I drove with it unplugged around my neighborhood and it drives better with it unplugged but still idle bad when parked ....I'm gonna buy a new maf sensor and see it this will fix it.

[van462]

I wonder if the exhaust cam has skipped a tooth on the timing chain.

[bluefox280]

I'm using Carista to get my codes.

Again... what were those codes? Be specific and post exact numbers and descriptions.
Saying you have "fault codes", but then not posting any details isn't going to give us clear perspective on what's going on.

- Erik