Does anyone out there have experience with the GMC 454? I have a 1998 K3500 that's hard to start when warmed up. It cranks fine. It just takes about three tries before it fires. And for some reason it fires as soon as you let go of the key on the third try. Its got a new fuel pump and pressure regulator because of another problem I was having with it. Its done this since I got the truck about a year ago. Its got 81K miles and doesn't burn any oil so I think the engine is still in pretty good shape although it is a dog for such a big engine. Any ideas?