2002 serria starting problems

I have a 2002 GMC serria P/U with what I believe is fuel problems. The truck has always started quickly on the first turn of the ignition. In the last few months something changed, and it would'nt start on the first try, but always fired right up on the second try. The truck has been running fine, no hesitation, sputtering, or anything to indicate any problems. The other day I was going down the road when it sputtered a few times and completely went dead. Couldn't get it started again, so had it towed home. I have replaced the fuel pump and fuel filter, but still wouldn't start. I did spay some cleaner in the intake to see if it would fire, and it did. What other problems could it be that is causing the truck not to start or run. Thanks