Re: S4 rough acceleration

[EICHSTEV@aol.com]

Gary said:

>> I have a 94 s4, bought at 87k,nearing 100k now and seems to have developed
a
>> roughness during acceleration.
>> Most noticeable at 3000 to 4500 rpm at half to full throttle in second
gear.

Phil replied:

> This might be 'Adam Marsden Syndrome', named for the proprietor of AM
>  Cars who first described it to me when I told him the symptoms on my
>  car.  On my engine, there's a metal section in the crankcase breather
>  pipe where it reaches the top of the engine and curves over the cam
>  cover to meet the multi-way hose junction on top of the engine.  During
>  accleration in second gear, G-force is strong enough to push this pipe
>  back onto the top of #5 plug - effectively shorting out the plug wire.
>  The solution was to cable-tie the metal hose section to the plug cable
>  shroud.  This trick has helped quite a few people.
>  Of course, there's always the standard possibility that it's the
>  multi-way hose junction itself - they crack, underneath.

Not possible.  The S4 AAN engine has one coil mounted over each plug and the
PCV system is entirely different than on the 10V cars.

I have heard that the coils or short wires from the coil to the plug can go
bad, causing a problem just as you describe.  Coils are expensive, wires less
so. The O2 sensor is possible cause of driveability problems.  

HTH!

Steve Eiche
'82 Not So Ur q 20Vt