Okay, so...I bought the car for a really good price. The oil pressure was dropping and I replaced the oil pump after having it towed to my house, replaced the o2 sensors, maf sensor, turbo, and spark plugs...but my car is still throwing codes for no activity of the oxygen sensors, low circuit for the maf sensor...and its running rich...could this be an ECU problem?

 

First thing to check would be the engine grounds and the engine wiring harness grounds. Loosen them and re-tighten them to reestablish a good contact.

On the O2 sensors, what was the code you were getting on them. There are 2 per cylinder bank. One before the cat and one after. If you have a V-6 or V-8, there are 2 banks so there will be 4 O2 sensors. The O2 error codes should tell you which one (before or after cat) and what bank it is on.

 

P0134 and P0140 are the codes in getting...it's a 98 B5 a4 Quattro with a 1.8t...so it's throwing codes for the two sensors...I'll definitely check the engine grounds...where would I look for them other than the one on the valve cover? Thank you for your help

 

I'm not sure on the A4's. Just follow the wiring harness around to where you'll see a bunch of wire ends grouped together and bolted to anything like the block or the body. Since the starter is working, I don't think any of the larger ground straps that ground the engine to the body are loose but check them if you see them. Also check the wiring harness for the O2 sensors from the connector back to the firewall, especially if it is near the exhaust anywhere. The wires could have gotten into contact with the exhaust and melted the insulation around them and grounded them out.