urS4 bucking

[Charlie Smith]

Earlier, Myles wrote:
> 
> I seem to be having a strange bucking problem with my 94 S4 that starts 
> when I push the car some.  Originaly I thought it was just the clutch 
> slipping, but I know it isn't now because I had it replaced (there was 
> other gear work to be done, so I had them replace the clutch too).  It 
> hasn't done this since I got my car back, but yesterday I pushed the car 
> pretty hard as I got onto the highway.
> 
> I went from third to fourth at around 6500 and after a second or so of 
> acceleration in fourth the car started to buck. When I brought the tach 
> to around 5000 in fifth a few minutes later it did it again.  The car 
> proceeded to do this at slightly lower and lower rpms during my hour 
> long drive until it was happening just above 3000 in other gears.  I 
> don't know if it was fuel cutting out, a misfire, or any of a dozen 
> other things. I know it has been burning a quart of oil every 1200 
> miles.  The spark plugs were replaced about a month ago, but it was 
> doing this before that. 
> 
> Originally I was thinking that I might need to have the coil packs 
> replaced, but after going through the archives I'm just confused.  It 
> could be fuel injectors or the michelin man hose.  Providing I'm not 
> running too late this morning I'm going to double check the spark plugs 
> and make sure they're the right ones and in there tight. This car will 
> be going back to the shop anyway because it went in without an oil leak 
> and came out with one.
> 
> Matt

That car shouldn't be doing that.

A couple things.  1200 miles to a quart of oil is way too much.  I'd do
a leak down test and figure out what's wrong.  That shouldn't directly
cause the misfiring though.

Second, the 20V turbo is very picky on spark plugs.  You should use
ONLY the spark plugs (brand and heat range) called for by the factory.
I don't know what they are off the top of my head, but find out and
then put in some new ones.  If you are running some other plugs, you
may be experiencing fouling / misfiring caused by them - agravated by
the oil consumption.

If you are not, you should be subscribed to the S-Car-List, which is about
just this type of car.  Send an email to:
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    - Charlie


  Charlie Smith   charlie at elektro.cmhnet.org  614-471-1418  
  http://elektro.cmhnet.org/~charlie   Columbus Ohio   USA

  95 S6 Quattro  -  24 PSI, RS2 6 speed, and other features  
  96 Dodge Ram   -  30 PSI, w/Cummins turbo diesel