Engine O2 sensor ?

[tigercity45]

Having some issues with my 87 fox. Idle is off and when driving it back fires when you let go of the gas and also won’t let me go past 3k rpm. Just stutters. But got a reader and all codes showed up at my O2 sensor and a fuel pump secondary circuit fault. Not sure if this is something that can cause these problems. What do y’all think

 

[KRUISR]

An O2 sensor that works intermittently would definitely cause drivability issues.

 

[General karthief]

Vacuum leak or low fuel pressure
you ever check fuel pressure?

 

[Mustang5L5]

Is this a mass air swap car? I’m assuming yes because the VSS code is 1989+ only.

If so, was the fuel pump monitor and VSS wiring connected to the ECU during the conversion? If not, that explains the code 29 and 96.

41/91 can be triggered by faults with the air injection system and clogs in the crossover tube. What’s the status of the air injection system? Hooked up? Bypassed? Partially deleted? Completely removed including crossover tube?