My sister’s truck, a ‘99 Silverado 4.3 V6 is having occasional non-start issues. I’ve never gotten it to happen to me but it’ll crank but not fire, then a few minutes later my dad will come out and try and it’ll be just fine. No codes or anything that I can pull. The ignition relay felt a bit warm so I swapped it with the starter relay (both are identical Hella relays) so now if it doesn’t start but also doesn’t crank I know it’s that relay, but my other thoughts are something wrong with the signal to the coil pack (conveniently mounted on the back of the engine where I can’t get it) or the weird spider fuel injection monstrosity (also where I can’t get to it easily). Anyone here have this issue before or have familiarity with these engines enough to knowif it’s something easy/common?