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 KiDD 810]

wow that stinks . What part of ny u from?

[onceover]

vacuum leak for sure. had very similar problems along with the idle issue.

[aaaudiprotein]

+1 on a possible vacuum leak. open your hood and try to listen to any unusual "sir sucking" sounds :)

[rocketheavy]

you have a serious vacuum leak. I got the same codes when I didnt put the valve cover breather tube on all the way after I replaced the rear coolant flange. It miss fired like a mo fo. Put the tube back on, reset the codes and now it runs like a dream.

[AudiNYA4]

thanks for the advice.... How would I go along finding the leak?

[aaaudiprotein]

post # 4 also try to see if any of the check valves are cracked
or the best way is to do vacuum leak test

[kwimberly]

thanks for the advice.... How would I go along finding the leak?

Make one of these:
http://www.a4mods.com/index.php?page...tml&category=5

And check the suction valve and hoses that are closest to the firewall - this is near the coolant reservoir: