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That backfire may have blown off some vacuum hoses or even blown intake gaskets so look around. Double check the firing order and distributor rotation. Timing rarely changes with electronic ignition, don't rule out valve timing, do a compression test to find out.

Where and what vacuum hoses would it have blew off if any and how do i know if it blew a intake gasket but why did it backfire and why does it sound weak when i try and start it i know the batterys good its only a few months old

I have a hunch your timing chain jumped. Any vacuum hoses that blew off would be obvious like the brake booster and PCV hoses, intake gaskets are usually checked with the engine running then spraying the intake with carb cleaner or starting fluid. The timing chain can best be checked with a compression test. Many parts stores will loan you a compression gauge.

Well if my timing chain jumped is that a bad thing or how do i go about fixing that and after thats fixed it should start or what