4.6 no start issue

[pb2624]

Wondering if anybody else has had a similar no start issue. I just finished up the timing guides & chains service and I have had the engine started & idling (8 - 10) times this week with no issue other than a pesky exhaust leak from the EGR exhaust tube. This afternoon I started the car again to check if I had the leak stopped (I did) and I was just probing the engine with my mechanics stethoscope checking for any strange noises before a test drive when it started sputtering and acting like it was misfiring. I tapped the throttle and it sputtered and died. When I try to start it now it just cranks an cranks but never lights off. No CEL on the dash and verified with the reader of and codes or codes pending. No dash lights other than ABS light and center triangle; current at 1/4 of a tank of fuel. The car has been starting right up and running like a sewing machine since the service prior to this afternoon. Any thoughts?