In the last couple years, I've had this happen twice; she'll crank and crank and crank but just never fire. Mess around with the Schrader valve, and voila! Vroom! Two years ago my mechanic neighbor used his fingernail to check for pressure and squirted gas all over himself. Last week, I put a fuel pressure gauge on it, suspecting the fuel pump. I did have 60 when the pump ran, then it dropped and held at 58psi. My Haynes says I should have 60-66, and I don't imagine 2psi would make the difference in whether the truck actually starts or not. But of course she started after this test. I assume I should do my fuel pump regardless, as the big ol' gurl has 230,000kms on her and her pump is certainly noisy. Sat beside a co-worker's unit and couldn't even hear his pump over mine, and his was done last year. I'd hate to be stranded out in the mountains hiking half-way home to get cell coverage to call a tow truck! But why does messing with the Schrader valve wake her up? Am I getting some kind of vapour lock? Or is my pump enjoying messing with my mind? My Bourbon: 1999 GMC K2500 SLT, 230Kk, no real mods, just slowly replacing old bits with brand new ones. Soon I'll have a brand new '99 Suburban! I thank you all in advance for your consideration!