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Misfire, no acceleration, rough idle

Old 07-20-2018, 07:13 PM
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Default Misfire, no acceleration, rough idle

I need some help. I started my car yesterday and it started up but would barely idle, sat around 200 rpm. When pressing on the accelerator the the idle became even more rough and or stalled. I was able the start the car back up but the same thing happened.

So I let the car set over night and the next morning it started right up and was able to drive it like normal. Then today when leaving work the issue started again and would barely idle and and wouldn't accelerate and eventually died and wouldn't start anymore.

The car is throwing codes...
p0300 - random multiple misfire
p0174 - system too lean bank 2
p0305 - cylinder 5 misfire
p0306 - cylinder 6 misfire
p0106 - map sensor

Last time i checked the car has a MAF sensor and not a map sensor. Since I don't know audi systems that well i figured i would ask for some input. Does this sound like a vacuum leak, bad MAF, fuel pump or what?

Any help would be much appreciated.
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Old 07-20-2018, 07:35 PM
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If it's a D2 A8/S8 (you did not say) I'd think fuel pump. Try a puff of starting fluid, you can shoot into a vacuum line if you do not want to take the intake apart.
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Old 07-20-2018, 07:56 PM
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Yes it is a D2 S8.
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Old 07-21-2018, 03:17 AM
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sounds like fuel pump is gonna die,same thing happened to me.
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Old 07-21-2018, 05:49 AM
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What does everyone do when this happens? Can you only buy the whole fuel pump housing and assembly? Do you really have to drop the tank or can it be accessed from the top of the tank?
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Old 07-21-2018, 06:09 AM
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There are some writeups on it and some good youtube videos. In fact I have a pump I may go install on my S8 in a few minutes, I bought one to replace before the stocker wears out. It is important to get he correct pump, the wrong one causes you to run out of gas at 1/3 or so of a tank left, good info here:

https://www.audiworld.com/forums/a8-.../#post23892689

There are many posts with tips on this and the other D2 forums. I just got 2 of them, one for each of my D2s, paid $140-ish each. The best deal was when I had an ebay coupon and I got a VDO from partscontainer and they shipped it fast for under $130 (after coupon). It might be possible to save some money and get one from Europe. I got burned getting an MTM from Poland, it almost worked but when the tank was low I had the same symptoms as you did and in bench testing I found the pump to not be able to produce enough pressure to run the scavenge system.

-Joel.
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Old 07-21-2018, 06:40 AM
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You dont have to drop the tank,but it has to be installed correctly and i would install new gaskets too,200$ish for gaskets only.Do it right way and avoid doing it twice.
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Old 07-21-2018, 06:59 AM
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This VDO pump seems to be the correct one? VDO pump

Where can I get the gaskets at?
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Old 07-21-2018, 07:10 AM
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Yes that's the one I bought. Europaparts was cheaper w/o the ebay coupon but I do not know of a coupon running now. Europa's cheap shipping option was REALLY slow (smartpost) but I think the other shipping options were pretty reasonable.
Gaskets are expensive, I have reused them myself and so far have gotten away with it. There is a thread on the other USA-based D2 forum about them recently.
The thing I hope to do this time is not overtighten the long bolt and put the little cracks in the pump assembly top that led to the P0442s I got after I did the first pump in my 2001 some years ago.
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Old 07-21-2018, 07:20 AM
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A couple hundred dollars is not a big deal considering I thought I was going to have to to pay over $1100 for the whole fuel pump assembly. Is audizine.com the other forum you speak of?

And don't over tighten the long bolt, noted.
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