I have a problem, but I'm not sure what it is.

I drove the Camaro to work the other day and it was running fine. On the way home it started stumbling and knocking under acceleration, but no SES light. I stopped and checked under the hood, no loose wires or lines. I pulled out and merged with traffic and it was still bogging down. I stepped on the gas a little harder and still the same, nothing. So I push the accelerator to the floor and it takes off like a bat out of hell. I'm assuming the PCM went into open loop mode. I stumbled home and hooked up my Auto Xray scanner. No trouble codes found, under Op data everything was fine except the right O2 sensor. The reading was R O2 Sensor Ready. The left O2 sensor reading was 792 mVolts. So I replaced both sensors, fire up the car and it's still doing the same thing. I rechecked the connections and wires and I still had the same problem. I drove the car scanning it each time I stopped. I kept getting the same reading for the right O2 sensor. The left sensor was between 750 and 850 mvolts. The stumbling, bogging, knocking happens if it's cold or hot. There is still no SES light.

Car is a 94 Z28 A4 Stock 125,000 miles.

Plugs and wires are about a year old.

Fuel pump is about a year old.

Air filter and fuel filter are 1 month old.

Any ideas?

 

It would appear the left sensor is indicating it's running rich. As a result, the PCM is probably pulling fuel so look at the fuel trims. There are 2 things you can do to find the problem. First, if you disconnect the O2, the PCM should indicate about 450. Second if you short the black wire to the tan/white and purple/white wire of the O2, the reading should then be below 200. If either of those don't happen, you probably have a wiring issue.