# Surging/Misfiring 2.8 30v



## Slayer2.8 (Sep 21, 2007)

I have a '99 A4 2.8 30v.
The problem is that from idle to around 2500rpm the engine feels like it is surging/misfiring, almost like it wants to stall.
it also happens occasionally at higher rpm.
The car has 235000km on the clock and doesnt deem to be using oil.
What could be causing this problem.


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## dannebrog (Jan 9, 2005)

*Re: Surging/Misfiring 2.8 30v (Slayer2.8)*

I'm experiencing the same thing, or something similar. Under moderate acceleration bewtween, oh, 15-40 mph there's some pretty severe but short bursts of misfiring and hesitations. Temp is normal, fuel has been premium, all scheduled service done except 70k, but I'm only 2k over that point now. 2001 A4. Anyone got ideas? Knock sensors? O2 sensor? Bad gas? Clogged injector(s)? Mass flow sensor?


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## YavoR32 (Jul 31, 2006)

Injectors rarely get clogged... atleast on my jetta, and premium fuel keeps things lubricated.


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## EuRoTrAsH351 (Jun 13, 2004)

*Re: Surging/Misfiring 2.8 30v (Slayer2.8)*

I just purchased my car a week ago and I have experienced the same situation as Slayer2.8. I have done a complete maintenance overhaul to include but not limited to wires, plugs, air filter, valve cover gaskets, battery maintenance, fuel injection cleaning etc. All I have left to do minus replacing the clutch, flywheel and diagnosing the transmission, is to change the transmission fluid and fuel filter.
I used a handheld OBDII scanner and found all systems to be running at manufacturer standards. I also had the dealership inspect my car prior to purchase and also my mechanic did his own inspection as well. I myself would like to know what's going on as well. I'll report my progress as I go along.


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## dannebrog (Jan 9, 2005)

*Re: Surging/Misfiring 2.8 30v (EuRoTrAsH351)*

I'm going to try running a can of BG 44K fuel system cleaner through. My mechanic buddies swore by the stuff when I worked at a Honda shop years ago - pricey though, about $20/pint in 1995, and still available only to pro mechanics. Now I see they have a whole treatment you can have an equipped service station perform for about $120. Who knows, I'll try anything at this point. http://www.bgprod.com/home.html After that I may replace plugs - who knows, maybe they're shot.


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## EuRoTrAsH351 (Jun 13, 2004)

Have you checked to see if your fuel filter is bad? I know mine is and I have to have it changed A.S.A.P. If it's clogged, it may be causing issues. I tried some fuel system cleaner from Kragen. But I don't think that stuff does much. I'll check out that link you posted to see what it's about. Thanks for the info! http://****************.com/smile/emthup.gif


_Modified by EuRoTrAsH351 at 9:41 PM 10/7/2007_


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## EuRoTrAsH351 (Jun 13, 2004)

*Re: Surging/Misfiring 2.8 30v (dannebrog)*


_Quote, originally posted by *dannebrog* »_I'm going to try running a can of BG 44K fuel system cleaner through. My mechanic buddies swore by the stuff when I worked at a Honda shop years ago - pricey though, about $20/pint in 1995, and still available only to pro mechanics. Now I see they have a whole treatment you can have an equipped service station perform for about $120. Who knows, I'll try anything at this point. http://www.bgprod.com/home.html After that I may replace plugs - who knows, maybe they're shot.

The only thing I don't like about this product is that it says "NOTE: After cleanup with BG 44K® Power Enhancer,® regular use of BG Supercharge®II, Part No. 202, in gasoline engines...will prevent deposits from forming in the fuel system and upper engine for maximum driveability and fuel economy."
To be honest, it just sounds like a useless product. I think using the BG 9210 Inject-A-Flush® Apparatus with the BG Fuel Injection System Cleaner & BG Air Intake System Cleaner is your best bet. It's going to use high dissolving liquids with concentrated high powered air pressure to knock out the build-up and deposits. Don't waste your money on the other stuff. IMO. I hope this helps with you situation. http://****************.com/smile/emthup.gif


_Modified by EuRoTrAsH351 at 9:42 PM 10/7/2007_


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## EuRoTrAsH351 (Jun 13, 2004)

I'm just curious if anyone has had any luck with this situation? Nothing on my end. Let me know. I'm working on a solution and when I get my electronic version of the Bentley repair manual, I will have a better knowledge of the situation. At least I hope so.


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## PinoyxA4 (Sep 27, 2007)

*Re: Surging/Misfiring 2.8 30v (Slayer2.8)*

My best suggestion to all of you, buy some carburator spray and clean your intake manifold. If you can, try to take the carb out and clean it good, Is your weather temperture changing? Are you starting your cars in the morning? Try to clean the intake manifold, and if you dont know where that is, just follow your air filter and see where the black tubing leads too!


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## EuRoTrAsH351 (Jun 13, 2004)

*Re: Surging/Misfiring 2.8 30v (PinoyxA4)*


_Quote, originally posted by *PinoyxA4* »_My best suggestion to all of you, buy some carburator spray and clean your intake manifold. If you can, try to take the carb out and clean it good, Is your weather temperture changing? Are you starting your cars in the morning? Try to clean the intake manifold, and if you dont know where that is, just follow your air filter and see where the black tubing leads too!









Part of my tune-up maintenance routine involves cleaning out the throttle body with the appropriate cleaner but it's not as easy as expected with this car. I haven't looked at the manual, but is the throttle body behind the engine? I would assume so, since all I found was the MAF and the Air Temperature Sensor up top in the plastic and rubber piping. Thanks. http://****************.com/smile/emthup.gif


_Modified by EuRoTrAsH351 at 8:08 PM 10-6-2007_


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## PinoyxA4 (Sep 27, 2007)

*Re: Surging/Misfiring 2.8 30v (EuRoTrAsH351)*

yes, the throttle body and intake manifold is located towards the back of the engine.


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## EuRoTrAsH351 (Jun 13, 2004)

*Re: Surging/Misfiring 2.8 30v (PinoyxA4)*


_Quote, originally posted by *PinoyxA4* »_yes, the throttle body and intake manifold is located towards the back of the engine.








how exciting...
To be honest, the more and more I work on this engine, the more and more I know why VW/Audi killed it off. It's a pain in the a$$. No doubt. I'd like to score a 3.2l VR6 off a VW or Audi and transplant it into my car. That would be nice!


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## PinoyxA4 (Sep 27, 2007)

*Re: Surging/Misfiring 2.8 30v (EuRoTrAsH351)*

lols, yes it would be nice!


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## EuRoTrAsH351 (Jun 13, 2004)

*Re: Surging/Misfiring 2.8 30v (Slayer2.8)*

*UPDATE:* _I would strongly recommend that everyone that has been having this type of problem with their car, do the following:_
**Check the fuel system for any leaks and tears.
*Check all the vacuum lines (located above the throttle body actuator) for structural integrity as well as leaks and tears. 
*Change your fuel filter and make sure all fuel lines are clear of debris, contaminants, and anything else that shouldn't be there.
*Unclog the fuel injectors.
*Check to make sure that all corresponding electrical and mechanical components for said fuel system are in proper operation.*
_I don't recommend using any type of fuel injector or fuel system cleaners that you can purchase at Kragen/Autozone as they are not strong enough. There was a post earlier in this thread for an extreme option to clean out your fuel system completely. I would recommend something in that nature, once all the above has been said and done; as you can't really go wrong with it. I hope this helps anyone and everyone. http://****************.com/smile/emthup.gif_


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