Codes: P1113, P1171, P0171 and P0134

[Andys_Volvo]

Hello again,

I am back with a new post for a different car. It is a 98 S70 GLT with 313,000 miles on it. This car has had only minimal use in the last two years and has been parked outside. I did start and run it every two to three weeks or take it on short errands. In the year or so before I parked it I replaced the rotor, cap, wires and plugs as well as the fuel pressure regulator. While it was parked I did re-fill the tank with premium gas when necessary but with much less frequency. Due to the need to repair my new daily driver I have been driving the 98 regularly for about a week or so. I did need to replace the battery and evict a four legged tenant but once I did that the car started and ran without difficulty. After driving for a few days it was not as quick to start as it usually was, cranking for just a couple seconds before starting. Not a lot of hesitation but noticeable. It has gotten just a bit worse to the point that it will crank and sputter upon the initial attempt to start it. However, upon turning the key off and attempting again right away it will start immediately and then run fine without any hesitation, stalling or loss in power. It does not happen all the time and is NOT limited to just when the car has been sitting for an extended time. On at least one occasion it even sputtered when attempting to start it immediately after shutting it down. This too is irregular as most of the time it will start right up after only being stopped for a short period. Also there was still good pressure at the rail after it was sitting for an hour or so. I will check the pressure after it has been sitting overnight to see if there is any difference as I suspect maybe a bad check valve in the pump. I don't think it is a relay as I can hear the fuel pump running when I turn the key partially. The fuel pump is not the original. I replaced it a few years ago but did so with a cheap version. I am thinking that maybe the fuel is contaminated and/or the fuel filter is junked up. Any suggestions would be most appreciated.
Thank you.

[Andys_Volvo]

Checked pressure at the rail this morning and there was no pressure after sitting all night. Ran the pump a couple times, started and ran fine. Drove it and parked for an hour and a half then started no problem. Twice later it this morning after only shutting it off for a few minutes it stumbled on the first attempt to start but started up right away with the second attempt, immediately after the first.
By the way. There are no codes.