Volkswagen Repair: 2000 vw bug miss fire on all cyliders..., p0134, ho2s

Question
Hi =] My question is this... My 2000 2.0 VW bug is miss firing on all four cylinders. My dad changed the spark plugs and wires, made it worse, then he bought a brand new coil pack and changed that... no improvement. new fuel filter...checked for vacume leaks. when it is put on the computer, it reads out four codes, po134, po300, po301, po302. It runs horrible when idling and first taking off...after it warms up it runs fine. One other thing to mention, along with the check engine light that came on with this problem...also the temperature light came on always indicating that it is cold (it shows blue) maybe has nothing to do with the other problem???
Please help, he is changing the o2 sensor now...but he does not thing it would cause it to run bad.
Amy

Answer
The P0134 is the UPSTREAM O2 sensor.  Yes, this could cause the engine to run badly, but I'm not sure if exactly as you describe.  There are two O2 sensors, the first one(upstream) is between the engine and catalytic converter(CAT), usually close to the front of the CAT.  The second one is just after the CAT.  Change the upstream one and let me know how it goes.  Check out the link:
http://forums.vwvortex.com/zerothread?id=990129
Good luck.