b6 s4 4.2

i've been working with justanswer.com on this for a month now.... please read and let me know if you have any ideas/input

....if you help to fix the problem i will pay you $50 via paypal =)

http://www.justanswer.com/audi/4o460...when-open.html

 

so i guess i'll start from the begining... before i had any issues with this horrible misfire issue i was getting a code every once in a while for low threshhold in the cat... ( i have Fast Intesions DP's on with high flow cat, for aprx 10k miles) and though that either the ecu didn't like seeing less cats or an O2 sensor is getting lazy....

so a few weeks later the car starts to misfire pretty bad ( bearly stays running ) during open loop.... i asked justanswer.com what sensors the ecu looks at during open loop and they said MAF, CTS, and IAT.... all have been replaced with parts from ECSTuning.com...

-i've checked compression in all cylinders ( all good and even with eachother )
-i've checked resistance/OHM's in injectors ( all reading 15.2ohms )
- replaced spark plugs ( no difference ) ....checked and re gapped plugs to .85mm ( no difference )
- try'd swaping coils to different cylinders ( no movement on the misfires )
- try'd swaping plugs to different cylinders ( no movement on misfires )
- swaped injectors around ( no movement on misfires )
- checked wiring to CTS ( all good )... also, vag blocks look good on CTS (no sign of an open)
- checked fuel pressure (50psi)


looking at the vag com blocks 14,15,16,17 it seems that cylinders 1,3, and 5 misfire most of the time... are all of those cylinders on one bank?.... i had searched for a diagram of cylinder location and i though 1,2,3,4 were on the same bank and 5,6,7,8 were on the other.... is that right? cause if odd are on one side and even on the other then i could focus on what controls either bank... like an O2 sensor... i'm thinking of swaping my O2 sensors from one bank to the other and see if the misfire follows....

the car has 99,000 miles ( never replaced the O2's )
- chipped by SpeedTuningUSA.com
- intake
- dp's
- miltek catback

 

UPDATE:

the ecu does not look at O2 sensors during open loop... so it's most likely not that, lol... i think it may be the fuel pressure regulator witch on this vehicle is part of the fuel filter... replacing tonight, stay tuned!

 

in suspense...

Not 100%, but I do think that odd are on one side, even on the other...