4500rpm cutout and boost in neutral. Codes 2223 and 2342

[Dan Bozga]

    Hello everyone,
 
    I haven't been part of the list for some time now but I'd like to revisit an issue I've had with my 200. I didn't have time to mess with the car due to other priorities but I'd like to see if I can figure out the problem this time around.
 
   The car is a sedan with almost 200k on the odometer.
 
   My main concern is that I cannot rev the engine past about 4500 rpm. It gets stuck at that point and the tach needle bounces as if it's hitting a rev limiter. While this happens you can hear the car misfiring severely. The car acts this way wether it is in neutral or under load. Also easing onto the gas is the only way you can even get it up to 4500. If you try to give it too much it'll choke right away and start misfiring. The weirdest part is that it actually builds boost in neutral. I know I've said this before and nobody on here believed me so I'm including a video of  the phenomenon. The digital gauge in the car says it's building boost and so is the mechanical one I temporarily hooked up(this is a verified good gauge that I used in my B5 S4). The video shows vacuum at idle and boost when it hits that cutoff. Also you can see the tach and where it stops when you rev the car. It will never go past that no matter what you do and what the
 condition is.
 
   Here's a list of things I've done to try and track this down:
 
-Pressure test (all good and held at least 20psi from what I recall)
-Replaced ecu with another good unit
-I did a fresh headgasket, valve job and timing belt (timing is on 100%), I can attest there is nothing physically wrong with the engine
-Cams were checked for alignment at tdc and the Os line up as they should
-Replaced O2 sensor with original bosch unit 
-Replaced altitude sensor with good unit 
-New fuel filter
-New line from bypass valve to intake manifold
-Took bypass valve, spark plugs and wastegate frequency valve from my B5 S4. None of them made a difference
-Checked wastegate and it moved freely, not stuck. The diaphragm is also free of holes
-The car has no cats, they were gutted by previous owner
-I also disconnected the catback just to be sure so I can say the car isn't choking from clogged exhaust
-Took apart throttle position sensor, all contacts were good. I also measured it and it checked out
-Tested hall sensor and it checked out
-Tested RPM sensor and also replaced it with known good unit, which didn't help
-Checked all teeth and timing reference sensors on flywheel, nothing was amiss
-I believe I replaced the timing sensor too, which of course didn't make a difference either
-Maf was tested by someone and was told it checked out
-Checked pretty much every connector under the hood to make sure it had the right values and no faulty wiring
-Checked wiring leading to ecu, relays and fuse panel as best as I could. Didn't see anything odd
-Did output test, everything was normal. I don't think the carbon canister solenoid(or whatever it's called) was getting a signal though
-It makes no difference if the car is hot or cold. It always runs the same, sometimes it will start to idle very rough too and not really want to move at all
-Cleaned idle stabilizer valve
-Tested air temp sensor, which was fine
-All fuses are there and not broken
-Distributor has metal gear, no teeth cracked or broken on it or the camshaft
-I noticed some arcing from the distributor area one night while the car was idling, if I remember correctly it was around the hall sender
-The temperature gauge isn't always receiving a signal
 
   My brother was in front of me driving the car one night and it just wouldn't go anywhere(worse than before), then he said all of a sudden(and I saw this), the car took off as if something unclogged and it just pulled to 80mph. After that it started bucking again and never got "un-stuck" again. While I was behind him I saw a few little bright red pieces comming out the exhaust. They looked a lot like bright burning ash.
 
   When the car hits that 4.5k limit, you can hear a clicking in the ecu, like a relay. And the wastegate frequency valve will frantically start clicking away too once you've let the gas go. I've heard it under the hood quite a few times.
 
   Anyways, I'm not sure what else I can say about all this....I'm sure there are things I did which I forget. If I recall something else I will post it on here. Or if you have any questions about a particular part you didn't see checked, let me know.
 
 
    Do our cars have this issue at all? This is something about a 4k cutoff due to faulty brake light on intended acceleration:
 
http://www.intendedacceleration.com/tip_2.html
 
 
 
   And lastly, here is the video I recorded. It shows exactly what my car is doing:
 
http://www.youtube.com/watch?v=STydKk6Ja28
 
 
Thanks and sorry about the long e-mail. I just tried to include everything before I'm asked what I've done to diagnose this :)
 
Dan