1991 pontiac grand prix fuel filters

Im working on a 91 grand prix le with a 3.1 multiport engine. It has been sitting in the back lot at work for a long time, Ive changed fuel pump, sending unit, the filter down by the tank and the pressure regulator. I also flushed out the tank with clean fuel. Is the little canister that sits right before the pressure regulator a secondary filter? the haynes book does not even mention it, but i drove it the other night and it ran very strong for maybe a mile and a half then acted like it ran out of fuel. Its the only thing that is left in the fuel delivery system I havent changed. Thanks for any insight anyone might have. Getting tired of bussing to work. Thanks again ogige.

I don’t believe that’s a filter. I believe it’s a device similar to a shock absorber that helps keep noise down. I would be wondering about a plugged catalytic converter. Remove the oxygen sensor when it occurs again. Or test backpressure.