There are a lot of diffferent things possible, the backfiring is usually caused by a timing issue. Which could also cause some of your loss of power, but not always. Try checking your fuel pressure to see if there is a clog, also your timing is computer controlled so this means your timing chain is worn spark plugs and wires could be bad or you have a cracked distributor cap rotor bug bad, or even a bad distributor or even as simple as wrong ground placement for motor. Best choice is to start small and then work your way up. Also if disributor has ever been taken out then you will have to reset your oil pump drive because your distributor runs your oil pump with your cam-shaft.
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There are a lot of diffferent things possible, the backfiring is usually caused by a timing issue. Which could also cause some of your loss of power, but not always. Try checking your fuel pressure to see if there is a clog, also your timing is computer controlled so this means your timing chain is worn spark plugs and wires could be bad or you have a cracked distributor cap rotor bug bad, or even a bad distributor or even as simple as wrong ground placement for motor. Best choice is to start small and then work your way up. Also if disributor has ever been taken out then you will have to reset your oil pump drive because your distributor runs your oil pump with your cam-shaft.