Ok so just to double check i got this right...

The car ran fine ... It sats for 3 months ..You the replaced the fuel tank & pumps...It started up but it was back firing.. You then adjusted the valve lash..When your tried to restart it.. it would not start..

You then replaces the Fpr,fuel rail & injectors..You also check the firing order and it was fine.. Now it only starts with starter fluid..

So Now does the car idle fine and if you try to give it tad of gas it starts to backfire? Or as soon as you start it up its backfiring at idle??


I would say you have sticking valves..Could even be a damaged springs but i dont think it likely

And Being the car sat for 3 months it is not unexpected at all to have sticking valves..

There are a few things you can try to free up a sticking valve assuming its not slightly bent or warped and being hung up...

Try doing an oil change and adding marverl mystery oil.

I also heard that Amsoil power foam works pretty well..

But to be honest with you i would...Try pouring kerosene on the valve assembly, moving the valve up/down with the cylinder rotation- it should dissolve any sludge/grit/grime that may have accumulated and work it free. Then i would change the oil & filter and run marvel mystery oil or the amsoil power foam. The fire her up...

If that provides improvement, then you are likely in good shape.