Still on 4 cylinders...

[AUDIJIM at aol.com]

S-heads,

Here's a new one for you. I changed the oil in my S4. I used an OE Audi 
filter and Mobil 1 15-50. Now the car runs worse than it did before I changed the 
oil. It used to run on 4 cylinders as soon as you start it. Actually, it starts 
on 5 and then drops #4 until it warms up a bit and them hits on all 5. Now it 
runs on 4 for a lot longer duration than it used to. I'm seriously thinking 
of swapping another AAN I have on a stand into the car over Christmas break 
from work. I have off from the 24th through 03 JAN. I'll swap over all the RS2 
stuff and see what happens. I'm at a total loss here for this problem. I'm 
either tracking down a cylinder/piston problem or a cylinder head problem at this 
point. What throws me for a loop is the starting on 5 cylinders and always 
dropping #4. Even when I run the car on 4 cylinders, it starts to even out over 
3000 RPM. But I think it's only feeling like it is, as soon as I shift up, the 
RPM drops and I feel the missing cylinder. Back to the beginning, how could an 
oil change effect the running condition so much? I do not know what viscosity 
the previous owner used, and this was my first oil change since I purchased 
the car.

Jim