Crazy Engine Shuddering

[TurboNate]

I'm having an issue with my car, and I'm not 100% sure to what it is. When accelerating, the engine starts to shudder very rigorously. This started once I tuned to APR stage 1. It was once in a while, now it's every time. After countless hours of searching I came to the idea that it could be my coil packs/spark plugs. I'm not 100% sure because everyone with the coil packs being the issue had a check engine light (which I don't). I've ordered both coils and plugs and are waiting for them to arrive but I'm not sure if that's even the issue. Anyone have some insight? (I do not have a VCDS to scan)


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[pierreb]

Maybe an engine mount failing?

[TurboNate]

Maybe an engine mount failing?

What are the symptoms of a failing engine mount?


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[Liquid Smoke]

What are the symptoms of a failing engine mount?

pretty much what you're experiencing. the engine vibrates more as the mount is prob failing and giving less cushion, you feel it more during acceleration.

[TurboNate]

It's not vibrating. Like the engine is stuttering. Cuts off power and the car shakes


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[Liquid Smoke]

oh i see, if it's cutting off power and shuddering then it's prob not mounts then. seems like it could be the coils or plugs, they won't always throw a code that happens if there's a misfire, but who knows, maybe the coil isn't giving power properly but not really misfiring. are you able to put it into a stock tune mode and see if it still does the same thing? might want to check with APR too since their tune seemed to do it.

[TurboNate]

oh i see, if it's cutting off power and shuddering then it's prob not mounts then. seems like it could be the coils or plugs, they won't always throw a code that happens if there's a misfire, but who knows, maybe the coil isn't giving power properly but not really misfiring. are you able to put it into a stock tune mode and see if it still does the same thing? might want to check with APR too since their tune seemed to do it.

I have tried but arin suggested different gas, which didn't do much. I'm going to change the coils and plugs and see if that does anything. If not. I'm lost..


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[skis4hire]

Does it do this when you rev it in park/N?

When you say accelerating, what RPM? Does it happen just as the boost is really coming on?

[TurboNate]

Does it do this when you rev it in park/N?

When you say accelerating, what RPM? Does it happen just as the boost is really coming on?

Yes it does when I'm reving. And yes it does when there is boost. I'm not sure as to what RPM


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[Comp4k]

Yes it does when I'm reving. And yes it does when there is boost. I'm not sure as to what RPM


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I had this EXACT problem, turns out it was a failing PCV, PureMS diagnosed it by doing some vacuum testing. Here's the part that they replaced:

https://www.ecstuning.com/b-genuine-...v/06h103495ac/


Also, another symptom is fluctuating RPMs while idle. Basically the valve isn't staying closed under boost and is causing excessive crankcase vacuum. I'm at 75k miles- also needed 3 of my motor mounts replaced too :(.

[TurboNate]

I had this EXACT problem, turns out it was a failing PCV, PureMS diagnosed it by doing some vacuum testing. Here's the part that they replaced:

https://www.ecstuning.com/b-genuine-...v/06h103495ac/


Also, another symptom is fluctuating RPMs while idle.

If the coils/plugs don't fix it I'm definitely going to try this! Thank you so much. (Coils arrive tomorrow, installing Tuesday morning)


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[Comp4k]

If the coils/plugs don't fix it I'm definitely going to try this! Thank you so much. (Coils arrive tomorrow, installing Tuesday morning)


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Yep, I too thought it was sparks at first but no misfire codes. Also, my car is Stage 1 APR too.

[TurboNate]

Yep, I too thought it was sparks at first but no misfire codes. Also, my car is Stage 1 APR too.

Damn there goes another $150


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[TurboNate]

**UPDATE**

CEL turned on today. Scanned it with OBDII and got P0303 (misfire in cylinder 3). The CEL was flashing for about 5 seconds then went way.


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[TurboNate]

**UPDATE 2**

Went to clear codes and Carista stats's that my voltage is too low... alternator was just changed, is the battery bad now?


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[TurboNate]

Just got out of class to check the battery level. It's now dropped to 80%... was at 90% before class. Is this normal Or am I in trouble


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[Comp4k]

**UPDATE 2**

Went to clear codes and Carista stats's that my voltage is too low... alternator was just changed, is the battery bad now?


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How old is your battery? I had to get mine changed at the 5 year mark.

[TurboNate]

How old is your battery? I had to get mine changed at the 5 year mark.

No clue but I got it tested at my mechanics shop and he said battery is fine


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[KompressorLOgic]

When I was stage one id occasionally get that stutter around 2800-3000 under high load(full boost) going up a hill or something when the trans hasnt downshifted, Too me it felt like either a missfire or detonation. B8 6zf tip. I never had a cel throw.

It still very rarely does it with stage 2 but I usually try to avoid that kind of scenario.

[TurboNate]

When I was stage one id occasionally get that stutter around 2800-3000 under high load(full boost) going up a hill or something when the trans hasnt downshifted, Too me it felt like either a missfire or detonation. B8 6zf tip. I never had a cel throw.

It still very rarely does it with stage 2 but I usually try to avoid that kind of scenario.

That's how it was when I first got the tune! But it's progressively gotten worse and worse now it's really bad.


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[TurboNate]

Changed the coils and plugs. No more studdering/shuddering!! How ever over night the battery life dropped to 70%.. I had checked it with my mechanic and he said it's good. I checked with my tool this morning and it says it's good. Anything that could be draining power? Could it have been the bad coils?


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[TurboNate]

**UPDATE**

Went to go start up the car and now it has very rough idling, and misfiring in cylinder 4. Tried switching coils around and spark plugs and it's only in 4, getting code P0304. Removed PCV valve to check if it's bad, the flap is fine. It's not stuck open. Any ideas?


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[Townending]

Injectors? Not an quick job, but you can swap the injectors around to see if the misfire follows the injector.

[TurboNate]

Injectors? Not an quick job, but you can swap the injectors around to see if the misfire follows the injector.

Injectors were replaced 2k miles ago after carbon cleaning


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[pierreb]

What year car and mileage? Could be your timing is screwed up from bad tensioner or something in the head is damaged like a guide.

[b6Hate4]

All we are doing here without VCDS is basically shooting in the dark, or playing throw money at the problem....

You need a proper scan to diagnose what is happening to get a starting point for us.

[s4baby]

I would try the PCV. I had a P0303 and a new PCV fixed the problem. $85 for the part from the dealer.

Not sure what you mean by PCV flap, mine had a tear in the rubber diaphragm.

[TurboNate]

All we are doing here without VCDS is basically shooting in the dark, or playing throw money at the problem....

You need a proper scan to diagnose what is happening to get a starting point for us.

I would try the PCV. I had a P0303 and a new PCV fixed the problem. $85 for the part from the dealer.

Not sure what you mean by PCV flap, mine had a tear in the rubber diaphragm.

I went to the dealership and purchased new coils from them, went home and it was great. Started up like a champ. Did some 2nd and 3rd gear pulls and it was amazing. Best I've felt it since tuning it. Go home and turn off car then want to take my mom to go shopping and it takes a good 3 seconds to crank. Usually 1 second to turn over. I get a CEL, then scanned it. I got about 3 codes. (See attachments). Reset codes and drove it. RPM's were fluttering around 2k-2.5k. Went away and now it's fine? I'm getting annoyed with all the problems



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[b6Hate4]

I would try the PCV. I had a P0303 and a new PCV fixed the problem. $85 for the part from the dealer.

Not sure what you mean by PCV flap, mine had a tear in the rubber diaphragm.

P0303 is just a cyl. 3 misfire.

The fact that he is getting a code for multiple, and 4 makes me think it is a fuel pressure issue, since there is a code for that, and since the 4th injector is the last to get fed, and will be the first to suffer fuel pressure/ volume issues.

I'd bet a dozen donuts that you have a clogged fuel filter, failing sending unit (pump in the tank) or a failing HPFP. All signs point to it.

[seangrimes590]

P0303 is just a cyl. 3 misfire.

The fact that he is getting a code for multiple, and 4 makes me think it is a fuel pressure issue, since there is a code for that, and since the 4th injector is the last to get fed, and will be the first to suffer fuel pressure/ volume issues.

I'd bet a dozen donuts that you have a clogged fuel filter, failing sending unit (pump in the tank) or a failing HPFP. All signs point to it.

If this is indeed the case you need to be careful of high boost / high load situations, running lean is a disaster waiting to happen.

[TurboNate]

If this is indeed the case you need to be careful of high boost / high load situations, running lean is a disaster waiting to happen.

P0303 is just a cyl. 3 misfire.

The fact that he is getting a code for multiple, and 4 makes me think it is a fuel pressure issue, since there is a code for that, and since the 4th injector is the last to get fed, and will be the first to suffer fuel pressure/ volume issues.

I'd bet a dozen donuts that you have a clogged fuel filter, failing sending unit (pump in the tank) or a failing HPFP. All signs point to it.

So you guys recommend changing the fuel filter?


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[b6Hate4]

So you guys recommend changing the fuel filter?


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I would definately start there. Its cheap and easy. How many miles are you currently at? Just out of curiosity.

[TurboNate]

I would definately start there. Its cheap and easy. How many miles are you currently at? Just out of curiosity.

About to hit 104k


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[TurboNate]

**UPDATE**

Preformed a low amp trickle charge on battery yesterday and it seems to have fixed the draining issue. Haven't gotten any CEL any misfiring or anything. Good those codes may have been a glitch or something?


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[B8Brit]

So my ‘11 A4 2.0T Quattro auto started stuttering under acceleration yesterday. Like it was misfiring or something. Put it in neutral and she purred perfectly all the way up to redline. I’ll throw the Carista on in a few and let you know what i find.


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[B8Brit]

IMG_2348.JPGIMG_2347.JPG


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[Slick_B8]

All those codes lead to a bad intake manifold and may be leading to unwanted air into the system

[B8Brit]

Yeah trying to find an intake now....


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[Roadtrippn]

Yeah trying to find an intake now....


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https://www.eeuroparts.com Had the best deal I could find on a b8 intake manifold. I wanted to push my car off a cliff it was running so bad lol

[adamleaf8601]

https://www.eeuroparts.com Had the best deal I could find on a b8 intake manifold. I wanted to push my car off a cliff it was running so bad lol

Before you replace the intake manifold, check to make sure it’s faulty. On certain B8s Audi extended the coverage for both the injectors and the intake manifold.