1992 F150 4wd 302 auto
i see a lot of forums discuss the tfi modules without any real conclusions. which is the better module...the black or the grey one? will it hurt the vehicle if its a grey one originally and gets replaced with a black one, or vice versa? The truck has a hard start issue, gets worse when truck is at operating temps and shut off. crank for maybe 15 to 25 seconds no start, turn key of and crank again again maybe 10 seconds and she fires up. its not fuel related, nor is it ignition related, so im thinking TFI issues. any clarification would be appreciated as the parts store only has black modules and the truck currently has grey one.

thanks in advance