[s-cars] Car runs like crap under load

[Jason Butler]

I have somehow pissed the Audi gods off, within the last three weeks I've 
had a timming belt that slipped three teeth a blown tire a bad fuel pump and 
now this.  The car is a '93 S4 with stock everything.   It Idles fine and 
drives ok with no load on it but if I get over 5 PSI boost it cuts out and 
stumbles.  I get a code of 2342 which is O2 sensor, ignition problem, fuel 
tank empty (it's not this one), air leak etc..  anyone have any BTDT. 
things I've done in the last three weeks

    Replaced timing belt.
    Replaced water pump.
    Replaced Spark Plugs.
    Replaced Fuel pump.


Any advise would be apreciated

Jason