Got a 91 Z28 converted from 305 tpi to 350 tpi. 4.10 gears, 2200 stall converter. Edelbrock headers, Crane cam with 4:88 lift and duration of 224. edelbrock etec alum heads (64 cc) and intake. 24 lb accel injectors. Was running fine, but started to back fire through intake I think and shut off while driving. Now won't start at all. Fuel filter, pump, sending unit all new. could it be the accel injectors?

 

A TPI with steep gears, moderate stall converter, and longer duration cam? That's all on the edge of a mismatch. The converter isd O.K., and the 224 duration would be O.K. with more stockish heads, but paired with a stump-pulling set of gears may not make it the most suitable for daily excursions. All that still doesn't explain the backfiring and no-start, however. Was there any reprogramming done to adjust for the injectors, different MAP, and VE?

If you monitor standing fuel pressure after shutdown, you should be able to determine if injectors are leaking. You could also pull the plugs to check for fuel fouling.

Any spark? Does it have an aftermarket ignition amplifier/control (like MSD)?