I have a 1997 k1500 350 that just this afternoon decided it would not start. Ran fine all day yesterday but this afternoon would buck and stumble while attempting to start. I had this problem last year and the culprit was a cracked distributor cap. So my first course of action was to replace both the distributor cap and rotor. Still stumbled and bucked while attempting to start. Next, I checked all the fuses in both engine and passenger compartments all of which are fine. I then checked spark with an old plug and it produced a nice strong blue spark. After a new set of plugs I noticed there were two on the drivers side that were fouled pretty badly with somewhat grainy deposits on the ends. Tried starting again and the vehicle still stumbled but did not buck much at all (seems like a slight improvement). Consulted a local auto shop, where they loaned me a fuel pressure testing guage. I was told a reading of anything below 60psi and the vehicle will not start, anything above would be sufficient. Upon testing pressure yeileded consistant 62-63 psi readings. I then bled off a quart mason jar of gas for inspection, I noticed some sediment in the bottom and a bit of water along with amber colored fuel. My next step was to bleed around 1 gallon of gas from the tank hoping if there were sediment or water it would be removed. After doing so I replaced the fuel filter, bled another 2 quarts through the valve on the fuel line before the intake and checked the third quart for sediment and water. The gas came out clean and water free. Again I tried starting the vehicle only to find my efforts were still in vein, the vehicle still stumbles while trying to start. Any suggestions are greatly appreciated.