1992 Pontiac Grand Prix 92 3 1 That Used Start Dream Until Had Stored Two Years

I have a 92 Grand Prix 3.1 that used to start like a dream until I had it stored for two years. Upon coming out of storage, it needed a fuel pump and filter to get it running and it's been a hard starter ever since. A local shop installed the pump and filter.

I pump the accelerator pedal numerous times (10 and then crank the engine, usually another 4 or 5 pumps of the accelerator between cranking attempts) then it starts and car runs fine for the duration of the drive.

If I go back to start it warm (after setting a half hour for example), it starts fine but after several hours or overnight in this fall weather, it's the same hard start so I'm currently hoping the techron fuel system cleaner will have a positive impact but am looking ahead to the next step, just in case. I'm running the fuel system/injector cleaner just in case there's old varnish inside fuel lines, etc. Years ago, best advice probably would have been 'change the carb' and that may have resolved the problem but now with fuel injection... Stumped.

It's a bit of a nuisance to start after setting but otherwise runs fine but I'd sure like to get it back to where it used to be which was turn the key to start and off she goes (or a single pump of the accelerator pedal worst case).

Thanks for any pointers...