3.8 issues..help please!!!

hey gyys, im having some serious problems with my 95 stang.me and my dad have tried everything.The car just turns over and over for like 10 mins and starts. its runs great buit the first 5 times it will not start, we have swapped the tps out,maf out,crank pos.sensor,new plugs, gas filter, just about everybolt on peice. now it doesnt even want to start AT ALL.its got new plugs wires and coil pack. i dont understand it tho.it turns over and sounds like its back firing through the intake. even when we use starter fluid it wont start, just load up and pop really loud. please any help u guys can give me will defiantly be appreciated.thanks in advance Shawn.
 
You've verified that all the plugs are firing? Have you put a timing light on each wire to see if the plug triggers it?
It's probably not a fuel problem, since it won't run on starter fluid either.
As long as you have compression and spark, the engine should start. It almost sounds like your timing is way off. Since it's a distributorless ignition, you can't adjust it, but your ignition module might be bad. The service manual has a procedure to check it with a voltmeter.