My Van is the 3500 5.7 L. was running fine up to this issue. When I crank the van I get sporadic hesitations but will not start, battery is fully charged, I have a spark (checked with timing light) but no ignition. Replaced the cap and rotor, I found some signs of wear. Used hand held diagnostic meter, no codes everything came back OK. When I attempted start up I got a major backfire out of the intake manifold, a weird thing started with this failure. When it cranks the speedometer jumps to 30 to 40 mph. but still does not start
I have fuel pressure at rail, so I tried spraying starting fluid into the intake to check possible injector fail, got backfire out of the intake manifold, it sounds like a timing issue, does the speedometer quark relate to a major computer issue or something smaller like a possible short or a positioning sensor fail?
What should I do next?