S4 #4 cyl miss update

[AUDIJIM at aol.com]

To answer a couple things that were asked about this issue:

"What did you write to this group for?"

Referring to the UrQ list: because many of you have AAN engines installed in 
your Urq's that's why.

"Do a cylinder leak down test and get back to us"

I performed a compression test and that gave me all the information I needed. 
In fact, cylinder #4 was the best compression of the 5 cylinders. A leak down 
test would not have given me any more information to trouble shoot this 
problem.

"Try swapping POS"

I swapped POS's and #4 cylinder was still dead.

Yesterday I spent all day playing with this problem. I performed an output 
test via VAG-COM. All output test functions operate normal. Unless I removed a 
fuel injector connector while the engine is running, I got no faults. Although, 
I did get one  fault: 01252 Fuel Injector cyl. #4 (N33) 31-10- Open or Short 
to Ground - Intermittent. Now I don't know If I got this because of removing 
the injector connector or if it was a true fault, but I concentrated my efforts 
there yesterday after I did the following. I installed all new F5DPOR plugs. 
I replaced the coil at #4 cylinder (no splicing, I did it the correct way) I 
made a new ground for the coils using a ground cable from an Airbus A320 
(thanks to Northwest Airlines) I swapped every POS I have with no difference in the 
running problem. The other day before I ordered a new coil, I pulled the fuel 
rail out with the injectors still attached, and laid some paper towel under 
them to see if they at least sprayed and made a wet spot on the paper towel. 
They did. Yesterday, I hooked up my remote starter and performed the same test 
with the injectors right in front of me. They all work very well. I also bridged 
the fuel pump and then I ran a positive and a ground lead to and from the 
injectors and they all worked as advertised. So I am ruling out the Fuel 
injectors and the ignition coil. I cut open the engine wiring harness and physically 
traced both wires to the ECU. Right after the firewall grommet, the wires head 
towards the passenger kick panel where they meet at a welded internal 
connection. The welded connection is crimped and soldered by the factory. All wires 
Ohmed out the same. I swapped my Lehmann ECU with a stock ECU. No change. I am 
left with replacing the POS in the event that I have 4 POS's that are doing the 
same thing to #4 cylinder or to change the engine wiring harness. Once the 
engine is at operating temperature, it runs great. When I start the car cold, it 
runs on 4 cylinders.

Any thoughts or comments?

Thanks,

Jim