94 3.8 cranks,no start

Brand new here guys so hello,I'm doing a freebie job for a family member here and I'm sure most of you guys probably been there too.its a 1994 3.8 5 speed,38 lbs of fuel pressure,it is jumping my spark tester so its firing,firing in order-I dont know,it seems as if the engine runs the same rpm or speed as the starter motor does but dies when the key is released from start to run it dies,if you can call that running,it also pops or backfires through the intake.Thanks in advance for any suggestions or tips

I worked on a '97 camaro that had the same problem. It was just a corroded coil/wire connection.