My '96 Chevy Z71 w/ 5.7L engine runs great, but starts hard. Somedays are worse than others. Hot or cold doesn't matter. It cranks and cranks and always eventually fires, but it just takes much, much longer than it used to. You can smell raw fuel after it starts if you are outside the passenger side.
I've replaced the fuel pump, fuel filter, battery, taken all battery cables (+ and -) off and removed any corrosion and reconnected with dielectric grease, replaced cap and rotor and plugs. I took the IAR (idle air control) valve out and cleaned with carb cleaner. I've performed every check my Haynes repair manual recommends in it's troubleshooting section.
A shop checked the computer for errors codes and came up with no errors. They had no idea what might be causing the problem and admitted they'd just start replacing parts until it was fixed.
Suggestions and/or thoughts? This one has me stumped.