OK guys, I could use some ideas here. My '97 Suburban, 5.7L, auto, K2500 has gone "No Start" on me. It was running 100% perfectly fine, no indication of any trouble, no DTC's, no nothing. I parked in my driveway Xmas day. It has been running in this terrible Washington weather, through cold and snow like a champ. I go to start it up yesterday morning, and it won't start. I keep trying for a bit, nothing. Motor turns over and acts like its _almost_ going to catch, but it never gets running. Since I could hear the starter beginning to slow down, I put the battery charger on overnight and let 'er charge up 100%. This morning, I go out and re-test. The starter cranks the engine quite nicely, it sounds like it normally does on startup. But the engine will not start. I squirted in a shot of starting fluid and re-tried, and I got a backfire, but no start. SO: I pulled the injector harness and put on a probe light. Yes, injectors getting power. Yes, fuel pump is running. Yes I checked the spark plug for spark, yes there is spark. But all I can get out of this is an occasional backfire.... NOTE: Occasionally the starter motor will suddenly slow down like it gets stopped in its tracks - almost like the engine is firing at the wrong time. That's why I was suspecting something wrong with the backfire. Any ideas where to look?? Is it possibly crank or cam sensor??