Car Trouble, Need Help

[AudiNYA4]

Multiple codes came up when I scanned my car Audi A4 03 1.8T:
P0300 - Random/Multiple Misifire
P0301 - Misfire Cyl 1
P0302 - Misfire Cyl 2
P0303 - Misfire Cyl 3
P0304 - Misfire Cyl 4

First tried to Resolve the Misfiring, replaced all coils and plugs , but misfiring still occurred. Took it to Audi and they told me it was due to faulty wiring to ignition coils. Wiring was replaced and misfiring stopped for a couple days, but today random misfires began to occur again and check engine light turn on and was flashing. Any suggestions on what else it can be?

Also other codes came up:

P1297 - Connection Charger Throttle Valve Pressure Drop
P0238 - Turbocharger Boost Sensor Circ. High
P0106 - Map Circ Range Performance

What can I do to fix these problems?

random car problems occurring:
When car is in Park or Neutral the tachometer is constantly revving between 1500 - 2500 rpm, but drops down to normal under 1000 when it is put in Drive or Reverse. What can cause this?

Also, information display signaled having low oil, but when checked it was regular. Then when I screened it again everything came up OK. This had occurred twice. What can cause this?

Any feedback and help would be highly appreciated.

[A4_Joe]

Which dealership did you take it in NY?? Also where was the last place you got your oil change?? Only reason why i ask is after the oil sludge issue audi did change their oil filter for 1.8t to bigger filter. But you have Oil sludge issue with your vehicle.

Way to test your vehicle.
start the vehicle & let it sit at idle, Then try to open the oil cap if it is hard to open the cap you do have oil sludge issue or its getting there. If it is hard to open the oil cap next step should be find your crankcase ventilation valve and follow the hoses & pinch them off and try opening the oil cap, after you pinch the line & if the oil cap is easy to open you found your problem. Most likely your crankcase check valve is faulty.

oil min light was problem occur because all the issue your having with your vehicle.

Hint- If you look under the intake manifold there is plastic piece that is connect to bunch of rubber hoses (which is the check valve) start tracing the hose & pinch them off and try opening the oil cap.

where in nY are you from?

[A4_Joe]

Here is the picture of the where check valve should be.



Another where the location is.

[AudiNYA4]

I live in Queens. I took it to Audi Manhattan and they told me it was the wiring, even tried to get me to change my coils and spark plugs again, but I was like no I just changed them. I think your right about the oil sludge, I removed the lid and there was black sludge... From my knowledge, isn't that covered under warranty?