Ok got some codes back:
P0134- oxygen sensor no activity bank 1
P0300- misfires
P0302- random misfire cylinder 2
P0304- random misfire cylinder 4
P0327- knock sensor

So i guess ill start with the 02 sensor and knock sensor and replace those first.

 

Have a question about these connectors to the sensors.
By color can someone identify them all

Again this is a 2000 a4 quattro 1.8t with the ATW engine code...

 

Going off my 2.8 I think from L to R its:
Rear o2 (brown)
Upstream o2 (black)
engine speed/crankshaft position (white)
knock (dark green)
knock (light green)

These are guesses because I don't have that engine. I'll look it up and see what I can find

edit: I thought the far right, light green one was a coolant temp but it appears to be another knock sensor. Interesting there's two for one bank.

 

Anyway, the o2 sensor is obviously a concern. I'm wondering if you unplug your MAF and try to start it will it run? My theory is that it'll stay in open loop so it won't look for the o2 sensor reading to run the car. It should still start regardless because it stays in open loop for the first few minutes of every startup anyway...

Misfires can certainly be cause by a bad o2 sensor so I would consider those secondary issues at the moment, but they may end up being the icm or plugs ...or really anything.

Never had a knock sensor go bad myself, but I would guess it just needs replacing.


I would start with unplugging the MAF and/or replacing the o2. Then clear the codes and see what comes back.

 

I would say O2 sensor as well. I've had similar issues and chased all kinds of things down, spending money unnecessarily when it was just the upstream O2. Start with the O2 sensor (only) first, then go (one by one) from there.

 

Ok i will try to unplug the MAF and see if it starts...but here's something else. I removed the cover to the fuel pump in the trunk and had someone try to start the car while i listened in the trunk and i couldnt hear anything like a fuel pump turning on...the relay seems fine because it clicks but nothing from the fuel pump itself. Is my fuel pump bad?

 

Do i have to open the MAF box to disconnect it or is there a way to do it from the outside?

 

Ok so i was able to disconnect the MAF and no it still wont start...continues to turn over just wont start.
Anything about the silent fuel pump...i should be able to hear it right?

 

If you were listening to the pump while the key was turned to the "on" position (not trying to start the car) and you didn't hear it prime for two seconds, then I would assume it's the pump.

I'm sure there's a way to test the pump in the car, but I can't tell you if it's a good idea or not, since you'd basically be sitting on a bomb.

 

Well i ordered a bunch of parts yesterday including a fuel pump so when i start to get them in ill change out parts one by one to see what the problem is....and im gonna clean the MAF sensor today since i have some time before parts start showing up.