So I have a 91 z28 5.0 TPI. The car starts up fine and no issues there when cold. Once it warms up though and I start driving around for about 10 minutes the car will start to surge a bit. It's not extremely bad but it is noticeable. I used my Autoxray diagnostic tool and got these results. I have a feeling that I have a faulty EGR but need some help.

PROM ID- 5301

Coolant temp- 167.9
Throttle sensor- 0.80 volts
Throttle angle- 7%
Engine RPM- 1462
Vehicle speed- 40
Oxygen sensor- 774 mVolts
MAP sensor- 2.19 volts
Manifold Air temp- 158.0
EGR duty cycle- 99.4
CCP duty cycle- 99.4
Battery voltage- 13.5
Fuel pump sensor- 13.1
Spark Advance- 35.3 degrees
Knock sensor- 3
Knock retard- 0 degrees
Injector pulse- 2.7 ms
CCP purge- on
rich/lean flag- fluctuates between rich/lean
Loop status- closed