91blackmustanggt

I have a 1991 mustang gt that has h/c/i and pretty much every bolt on part available except fuel pump which I have and need to install. I have removed the smog pump and the line running from the purge canister to the intake and blocked everything off. I plan to have the car tuned eventually but for now I am just using the air adjuster to adjust the air/fuel ratio.

I have run codes with the engine off and I get 67 O which is the neutral drive switch or manual lever position which can pretty much be ignored and the other is 96 C which says fuel pump secondary circuit fault / high speed fuel pump relay open. Could this code be causing my car to stall?

When I start the car I have to pedal it once or twice and then it idles smoothly for about 5 mins and then it surges for 5 seconds and stalls. My car doesn't reach operating temperature before it stalls but it does this to me every time I let it idle for 5 mins.