A4QuattroV6

Hi, I have a 1998 A4 with the 2.8 and recently, it has been running very rough intermittently. A lot of times, it runs perfectly normal but at random times for random lengths of time, it will loose power, run rough, and change to a much deeper pitch sound. It almost feels like a large intake leak post maf sensor. I thoroughly checked the intake from throttle body to Maf. I checked the maf connection. I checked the seal and the connection of the sensor further down the intake just outside the throttle body. I checked the breather hose connection to the intake just outside the throttle body. From there I checked over the entire breather hose system. The ENTIRE system. Also, I replaced every hose with 5/8" I.d. Heater hose that is much smoother and more durable than the ribbed oem plastic ones. I did this last spring. I then went over the ENTIRE vacuum hose system, which I also replaced with nicer vacuum hoses last spring. The ENTIRE system. With all that said, what could be causing the car to run rough and go back to normal at random for random lengths of time? Also, every time the car hit 5,000 rpm's, it will start running that way and then stop at its convenience. It does it at random when driving normal, but does it every time I hit 4 or 5,000 rpm's, then goes back at random. Some times it does it for a long time, other times not so long. But not once since it has started doing this, has it caused the car to stall or stop running. it just runs rough and weak and looses power and rpms wont raise and acceleration is very slow. Please help me with this. Thank you.

A4QuattroV6

Bump. Please help.

A4QuattroV6

P0134 - O2 sensor bank 1 no activity
P1196 - Slow response from oxygen sensor bank 2
P1197 - Slow response from oxygen sensor bank 1
P0102 - Mass Air Flow Circuit low input
P1432 - Secondary Air Injection Valve Open (this one has me the most curious)
P0300 P0303 P0304 P0305 Random cylinder misfire in cylinders 3, 4, and 5

Prospeeder

Sounds like a giant air leak to me, Missfires from being lean, no response from oxygen sensors because mixtures so far off, no maf input because its just pulling its air in from the leak point instead of through the maf to be read. So yea check for a giant air leak, boot to maf ripped, broken breather stuff, brake booster, vacuum lines, crankcase breather stuck open.